51edu.com
Free website and domain report on 51edu.com
Last Updated: 30th April, 2020 Update Now
Overview
Snoop Summary for 51edu.com
This is a free and comprehensive report about 51edu.com. 51edu.com is hosted in China on a server with an IP address of 118.190.77.51, where CNY is the local currency and the local language is Mandarin. 51edu.com is expected to earn an estimated $111 USD per day from advertising revenue. The sale of 51edu.com would possibly be worth $81,170 USD. This figure is based on the daily revenue potential of the website over a 24 month period. 51edu.com receives an estimated 26,290 unique visitors every day - a massive amount of traffic! This report was last updated 30th April, 2020.
About 51edu.com
| Site Preview: |   |
| Title: | 精品学习网 |
| Description: | 精品学习网是中国最大的教育门户和互动营销平台，内容涵盖八大考试门类和六大热门考试，提供最全面的教育学习和考试资讯，并提供考试交友，在线模考等多种学习服务。 |
| Keywords and Tags: | education, reference, 小 一 數學 練習 卷, 思想 汇报 十 九 大, 语文 知识 竞赛, 领导 力 案例, 高中 英语 知识 点 |
| Related Terms: | |
| Fav Icon: | |
| Age: | Over 21 years old |
| Domain Created: | 12th May, 2002 |
| Domain Updated: | 6th May, 2019 |
| Domain Expires: | 12th May, 2021 |
Review
Snoop Score
3/5 (Great!)
Valuation
$81,170 USD
Note: All valuation figures are estimates.
Popularity
High
Note: Popularity is estimated.
Rank, Reach and Authority
| Alexa Rank: | 29,813 |
| Alexa Reach: | 0.0021% |
| SEMrush Rank (US): | 5,773,063 |
| SEMrush Authority Score: | 50 |
| Moz Domain Authority: | 0 |
| Moz Page Authority: | 0 |
Rank By Country
| Country | Alexa Rank |
|---|---|
 China | 4,732 |
Organic vs Paid (Google Ads)
| Organic | Paid | |
|---|---|---|
| Keywords: | 321 | 0 |
| Traffic: | 41 | 0 |
| Cost: | $0 USD | $0 USD |
Traffic
Visitors
| Daily Visitors: | 26,290 |
| Monthly Visitors: | 800,193 |
| Yearly Visitors: | 9,595,946 |
Note: All visitors figures are estimates.
Visitors By Country
| Country | Visitors (Unique) | Percentage |
|---|---|---|
| China | Daily: 26,211 Monthly: 797,792 Yearly: 9,567,159 | 99.7% |
| Other | Daily: 79 Monthly: 2,401 Yearly: 28,788 | 0.3% |
Note: All visitors figures are estimates.
Revenue
Revenue
| Daily Revenue: | $111 USD |
| Monthly Revenue: | $3,384 USD |
| Yearly Revenue: | $40,580 USD |
Note: All revenue figures are estimates.
Revenue By Country
| Country | Revenue | Percentage |
|---|---|---|
| China | Daily: $111 USD Monthly: $3,384 USD Yearly: $40,580 USD | 100% |
| Other | Daily: $0 USD Monthly: $0 USD Yearly: $0 USD | <0.1% |
Note: All revenue figures are estimates.
SEO
Backlinks Analysis (SEMrush)
| Backlinks: | 2,570,793 |
| Referring Domains: | 9,191 |
| Referring IPs: | 8,890 |
51edu.com has 2,570,793 backlinks according to SEMrush. 100% of these backlinks are "dofollow" (follow) links which allow the flow of link equity to pass through, which may improve 51edu.com's search engine rankings. Other links are treated as 'hints' by search engines and may also pass link equity, depending on what search engines decide in each case.
95% of 51edu.com's backlinks are text and image links, which are ideal for SEO. Other backlink types may be unrecognized or ignored by search engines.
Top New Follow Links
1
Source: http://iaitew.me/
Target: http://img01.51edu.com/uploadfile/20140727/14064520951523.png
2
Source: http://iaitew.me/
Target: http://img01.51edu.com/uploadfile/20160331/1459390883744255.jpg
3
Source: http://iaitew.me/
Target: http://img01.51edu.com/uploadfile/20150830/1440925551383515.png
4
Source: http://iaitew.me/
Target: http://img01.51edu.com/uploadfile/20160927/1474940222941092.jpg
5
Source: http://iaitew.me/
Target: http://img01.51edu.com/uploadfile/20170809/1502260457697993.jpg
Top Ranking Keywords (US)
1
Keyword: 领导 力 案例
Ranked Page: http://www.51edu.com/guanli/glsj/415832.html
2
Keyword: 高中 英语 知识 点
Ranked Page: http://www.51edu.com/gaozhong/tbzsd/yingyu/
3
Keyword: 小 一 數學 練習 卷
Ranked Page: http://www.51edu.com/gaozhong/gaoyi/shuxue/shiti/
4
Keyword: 语文 知识 竞赛
Ranked Page: http://www.51edu.com/gaozhong/ywzsjs/
5
Keyword: 思想 汇报 十 九 大
Ranked Page: http://www.51edu.com/wendang/sxhb/fanwen/5763384.html
Domain Analysis
| Value | Length | |
|---|---|---|
| Domain: | 51edu.com | 9 |
| Domain Name: | 51edu | 5 |
| Extension (TLD): | com | 3 |
| Expiry Check: | |
Page Speed Analysis
| Average Load Time: | 3.99 seconds |
| Load Time Comparison: | Faster than 13% of sites |
PageSpeed Insights
Avg. (All Categories)
Performance
Accessibility
Best Practices
SEO
Progressive Web App
0–49 (Fail) 50–89 (Average) 90–100 (Pass) 
URL: http://www.51edu.com
Updated: 30th April, 2020
1.97 seconds
First Contentful Paint (FCP)
0.08 seconds
First Input Delay (FID) Simulate loading on desktop
Performance
Indicates how well the page is performing and highlights opportunities where performance may be improved for 51edu.com. This includes details about optimizing page load times which can result in a better user experience.Metrics
First Contentful Paint — 0.8 s The time taken for the first image or text on the page to be rendered.
First Meaningful Paint — 0.8 s The time taken for the primary content of the page to be rendered.
Time to Interactive — 0.8 s The time taken for the page to become fully interactive.
First CPU Idle — 0.8 s The time taken for the page's main thread to be quiet enough to handle input.
Max Potential First Input Delay — 30 ms Users could experience a delay when interacting with the page.
Other
Estimated Input Latency — 10 ms The time taken for the page to respond to user input (during the busiest 5 second window of page load). Users are likely to perceive 51edu.com as laggy when the latency is higher than 0.05 seconds.
Total Blocking Time — 0 ms The total blocking time is the sum of all time periods between First Contentful Paint and Time to Interactive (when task length exceeded 50ms).
Network Requests Below is a list of network requests that were made during page load.
| URL | Start Time (Ms) | End Time (Ms) | Transfer Size (Bytes) | Resource Size (Bytes) | Status Code | MIME Type | Resource Type |
|---|---|---|---|---|---|---|---|
| http://51edu.com/ | 0 | 1018.4189998545 | 255 | 0 | 301 | text/html | |
| http://www.51edu.com/ | 1018.8239999115 | 3836.5519999061 | 70217 | 69660 | 200 | text/html | Document |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 3852.5449999142 | 5206.0749998782 | 14525 | 13864 | 200 | text/css | Stylesheet |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 3852.7839998715 | 5481.6529999953 | 94287 | 93682 | 200 | application/x-javascript | Script |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js | 3852.7039999608 | 6354.0989998728 | 0 | 0 | -1 | Script | |
| http://www.51edu.com/images/logob.png | 3852.9409999028 | 13843.020000029 | 0 | 0 | -1 | Image | |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/images/xiala.png | 3853.5129998345 | 4429.5939998701 | 1839 | 1183 | 200 | image/png | Image |
| http://www.51edu.com/images/new.gif | 3853.5249999259 | 8858.3690000232 | 0 | 0 | -1 | Image | |
| http://www.51edu.com/images/hot.gif | 6356.5469998866 | 6667.6870000083 | 1638 | 999 | 200 | image/gif | Image |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 6356.6979998723 | 9898.9969999529 | 37374 | 53429 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 6356.838000007 | 7913.3279998787 | 30182 | 47438 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg | 3853.935000021 | 8863.1909999531 | 0 | 0 | -1 | Image | |
| http://cms.51edu.com/uploadfile/2019/1018/20191018052159549.jpg | 6357.2279999498 | 11222.73199982 | 13166 | 14701 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 6357.5399999972 | 10698.719999986 | 90583 | 105225 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 6358.0950000323 | 9125.2139999997 | 80130 | 92165 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 6358.2119999919 | 8921.10399995 | 32118 | 32889 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg | 3854.3139998801 | 16348.862000043 | 0 | 0 | -1 | Image | |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 6358.4199999459 | 10734.11199986 | 31853 | 41234 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 6358.5589998402 | 9643.5829999391 | 30843 | 40897 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg | 6358.6440000217 | 15599.670999916 | 26056 | 35679 | 200 | image/jpeg | Image |
| http://adm.baidu.com/img/vip_1.gif | 3856.1700000428 | 8863.5619999841 | 0 | 0 | -1 | Image | |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 | 4430.8879999444 | 6154.0679999162 | 4739 | 11794 | 200 | application/javascript | Script |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 | 6155.9939999133 | 7699.7599999886 | 4743 | 11794 | 200 | application/javascript | Script |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 6355.9279998299 | 7405.9629999101 | 96561 | 95957 | 200 | application/x-javascript | Script |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/com.js | 6356.1990000308 | 7148.6959999893 | 1779 | 1172 | 200 | application/x-javascript | Script |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/images/top1.jpg | 6365.114999935 | 7777.7690000366 | 1773 | 1123 | 200 | image/jpeg | Image |
| http://c.cnzz.com/core.php?web_id=2918556&t=z | 6586.9809999131 | 7181.2429998536 | 2263 | 3085 | 200 | application/javascript | Script |
| http://hzs19.cnzz.com/stat.htm?id=2918556&r=&lg=en-us&ntime=none&cnzz_eid=535619890-1588250431-&showp=800x600&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb66d55e4b-05abe1b4812fc9-6d274b2b-75300-171cb66d55f253&h=1&rnd=197108804 | 6587.5939999241 | 7278.1139998697 | 245 | 2 | 200 | text/html | Image |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=133339236 | 7184.878999833 | 7344.4850000087 | 605 | 0 | 302 | image/gif | |
| http://pcookie.cnzz.com/app.gif?&cna=18gxF8skXjgCAUPNiX8gI1a1 | 7344.8019998614 | 8040.5379999429 | 420 | 43 | 200 | image/gif | Image |
| http://c.cnzz.com/core.php?web_id=2918924&t=z | 7710.3409999982 | 8494.1779999062 | 1282 | 969 | 200 | application/javascript | Script |
| http://hzs19.cnzz.com/stat.htm?id=2918924&r=&lg=en-us&ntime=none&cnzz_eid=976571655-1588255447-&showp=800x600&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb66d55e4b-05abe1b4812fc9-6d274b2b-75300-171cb66d55f253&h=1&rnd=808016309 | 7711.1009999644 | 9147.2449998837 | 245 | 2 | 200 | text/html | Image |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=83401928 | 8497.4020000082 | 8640.9179999027 | 495 | 0 | 302 | image/gif | |
| http://hm.baidu.com/h.js?f23a13a09954dada8fad3e0691dfcf0f | 8502.6439998765 | 9214.3609998748 | 14801 | 40900 | 200 | application/javascript | Script |
| http://pcookie.cnzz.com/app.gif?&cna=18gxF8skXjgCAUPNiX8gI1a1 | 8641.0890000407 | 9218.6749998946 | 420 | 43 | 200 | image/gif | Image |
| https://hm.baidu.com/hm.gif?cc=1&ck=1&cl=24-bit&ds=800x600&vl=940&et=0&ja=0&ln=en-us&lo=0&rnd=191912894&si=f23a13a09954dada8fad3e0691dfcf0f&v=1.2.74&lv=1&sn=14724&r=0&ww=1350&ct=!!&tt=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0 | 9237.027999945 | 9559.6559999976 | 299 | 43 | 200 | image/gif | Image |
| http://share.baidu.com/static/js/shell_v2.js?t=7 | 9237.7659999765 | 10915.844999952 | 391 | 0 | 301 | text/plain | |
| http://bdimg.share.baidu.com/static/js/shell_v2.js?t=7 | 10915.996999945 | 11222.24799986 | 900 | 1135 | 200 | text/javascript | Script |
| http://bdimg.share.baidu.com/static/js/logger.js?cdnversion=441183 | 11225.124999881 | 11520.153000019 | 2733 | 5881 | 200 | text/javascript | Script |
| http://bdimg.share.baidu.com/static/js/bds_s_v2.js?cdnversion=441183 | 11225.422999822 | 12389.191000024 | 10321 | 26180 | 200 | text/javascript | Script |
| http://bdimg.share.baidu.com/static/css/bdsstyle.css?cdnversion=20131219 | 12397.538000019 | 12975.482000038 | 2344 | 9779 | 200 | text/css | Stylesheet |
| http://bdimg.share.baidu.com/static/images/r1.gif | 12422.610000009 | 13041.299999924 | 1257 | 980 | 200 | image/gif | Image |
| http://nsclick.baidu.com/v.gif?pid=307&type=3071&sc=1350,3489,800,600&desturl=&apitype=1&linkid=k9muae565v9&velo_load=1753&velo_cssload=581&velo_jsLoad=1197&cite_uid=10026&cite_type=4&cite_mini=1 | 17353.301999858 | 0 | 0 | -1 | Image |
Network Round Trip Times — 0 ms High Network RTT (Round Trip Times) can have a large impact on performance. Providing servers geographically closer to the user could improve performance.
Server Backend Latencies — 0 ms High server latencies indicate the server is overloaded or has a poor backend performance.
Tasks Below is a list of the top-level main thread tasks that executed during page load.
| Start Time (Ms) | End Time (Ms) |
|---|---|
| 3861.059 | 6.676 |
| 5504.407 | 19.981 |
| 6376.035 | 8.962 |
| 6385.255 | 204.615 |
| 6592.674 | 16.137 |
| 6608.875 | 40.247 |
| 7723.015 | 9.852 |
| 9237.595 | 57.445 |
| 12413.562 | 30.983 |
Opportunities
Eliminate render-blocking resources — Potential savings of 100 ms Resources, such as JavaScript and style sheets, can block the first paint of the page. 51edu.com should consider delivering critical JavaScript/style sheets (JS/CSS) inline and deferring all non-critical JS/CSS.
| URL | Size (Bytes) | Potential Savings (Ms) |
|---|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 14525 | 190 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 94287 | 310 |
Properly size images Images can slow down the page's load time. 51edu.com should consider serving more appropriate-sized images.
Defer offscreen images Time to Interactive can be slowed down by resources on the page. 51edu.com should consider lazy-loading offscreen and hidden images.
Minify CSS — Potential savings of 2 KB Cascading Style Sheets (CSS) files can contribute to network payload sizes. 51edu.com should consider minifying CSS files.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 14525 | 2511 |
Minify JavaScript JavaScript (JS) files can contribute to network payload sizes and increase script parse times. 51edu.com should consider minifying JS files.
Remove unused CSS Dead and/or unused rules in Style Sheets (CSS) can contribute to network payload sizes. 51edu.com should consider removing dead rules from style sheets and deferring the loading of CSS not used for above-the-fold content.
Preconnect to required origins Resource hints, such as 'preconnect' or 'dns-prefetch', may assist in establishing early connections to important third-party origins.
Avoid multiple page redirects — Potential savings of 190 ms Redirects can cause additional delays before the page can begin loading. 51edu.com should avoid multiple or unnecessary page redirects.
| URL | Time Spent (Ms) |
|---|---|
| (Start) http://51edu.com/ | 0 |
| http://www.51edu.com/ | 190 |
Preload key requests Key requests can be preloaded by using '<link rel=preload>'. 51edu.com should consider using '<link rel=preload>' to prioritize fetching resources that are currently requested later in page load.
Use video formats for animated content Large GIFs are inefficient for delivering animated content. It is recommended to use MPEG4/WebM videos for animations and PNG/WebP for static images instead of GIF.
Diagnostics
Avoids enormous network payloads — Total size was 687 KB Large network payloads can cost users money and are linked to long load times.
| URL | Size (Bytes) |
|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 96561 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 94287 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 90583 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 80130 |
| http://www.51edu.com/ | 70217 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 37374 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 32118 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 31853 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 30843 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 30182 |
Avoid chaining critical requests — 8 chains found Below is a list of Critical Request Chains, which shows which resources are loaded with a high priority. 51edu.com should consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
User Timing marks and measures Make use of the User Timing API to measure an app's real-world performance during key user experiences.
JavaScript execution time — 0.0 s JavaScript (JS) execution time can be lowered by reducing the time required for parsing, compiling and executing JS. Delivering smaller JS payloads may help with this.
| URL | Total CPU Time (Ms) | Script Evaluation (Ms) | Script Parse (Ms) |
|---|---|---|---|
| Other | 380.979 | 7.823 | 1.754 |
Minimizes main-thread work — 0.5 s Main-thread work timing can be lowered by reducing the time required for parsing, compiling and executing JS. Delivering smaller JS payloads may help with this.
| Category | Time Spent (Ms) |
|---|---|
| Style & Layout | 248.534 |
| Script Evaluation | 133.188 |
| Other | 77.811 |
| Rendering | 37.678 |
| Script Parsing & Compilation | 30.13 |
| Parse HTML & CSS | 20.77 |
All text remains visible during webfont loads Make use of the font-display CSS feature, which will ensure text is user-visible while webfonts are loading.
Keep request counts low and transfer sizes small — 43 requests • 687 KB It is advised to add a budgets.json file in order to set budgets for the quantity and size of page resources.
| Resource Type | Requests | Transfer Size (Bytes) |
|---|---|---|
| Total | 43 | 703682 |
| Image | 24 | 380441 |
| Script | 12 | 234409 |
| Document | 1 | 70217 |
| Stylesheet | 2 | 16869 |
| Other | 4 | 1746 |
| Media | 0 | 0 |
| Font | 0 | 0 |
| Third-party | 20 | 48503 |
Minimize third-party usage — Third-party code blocked the main thread for 0 ms It is advised to either limit, remove or delay the loading of redundant third-party code which may be significantly impacting load performance.
| Third-Party | Size (Bytes) | Main-Thread Blocking Time (Ms) |
|---|---|---|
| 33046 | 0 |
Budgets
Performance budget It is advised to keep the quantity and size of all network requests under the targets set by the provided performance budget.
Opportunities
Efficiently encode images — Potential savings of 230 KB Unoptimized images can consume more cellular data than what is necessary.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 90583 | 59573 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 80130 | 56774 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 37374 | 27109 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 31853 | 24451 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 30843 | 22916 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 30182 | 20500 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg | 26056 | 18874 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 32118 | 5666 |
Serve images in next-gen formats — Potential savings of 283 KB Image formats like PNG and JPEG have poor compression when compared to other next-gen formats, such as JPEG 200, JPEG XR and WebP.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 90583 | 73223 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 80130 | 68138 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 37374 | 31586 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 31853 | 27779 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 30843 | 26089 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 30182 | 25254 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg | 26056 | 21736 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 32118 | 16144 |
Enable text compression — Potential savings of 187 KB Text-based resources should be served with compression, such as gzip, deflate or brotli.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 95957 | 62639 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 93682 | 60166 |
| http://www.51edu.com/ | 69660 | 58643 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 13864 | 10164 |
Diagnostics
Avoid an excessive DOM size — 1,229 elements A large DOM (Document Object Model) will increase memory usage, cause longer system calculations as well as costly layout reflows.
| Statistic | Element | Value |
|---|---|---|
| Total DOM Elements | 1,229 | |
| Maximum DOM Depth | 11 | |
| Maximum Child Elements | 30 |
Metrics
Speed Index — 5.0 s The time taken for the page contents to be visibly populated.
Opportunities
Reduce server response times (TTFB) — Root document took 2,820 ms Time to First Byte (TTFB) identifies the time at which the server sends a response.
Diagnostics
Serve static assets with an efficient cache policy — 27 resources found 51edu.com can speed up repeat visits by increasing the cache lifetime, which is essentially how long before a cached copy expires.
| URL | Cache TTL (Ms) | Size (Bytes) |
|---|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 0 | 96561 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 0 | 94287 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/com.js | 0 | 1779 |
| http://hzs19.cnzz.com/stat.htm?id=2918556&r=&lg=en-us&ntime=none&cnzz_eid=535619890-1588250431-&showp=800x600&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb66d55e4b-05abe1b4812fc9-6d274b2b-75300-171cb66d55f253&h=1&rnd=197108804 | 0 | 245 |
| http://hzs19.cnzz.com/stat.htm?id=2918924&r=&lg=en-us&ntime=none&cnzz_eid=976571655-1588255447-&showp=800x600&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb66d55e4b-05abe1b4812fc9-6d274b2b-75300-171cb66d55f253&h=1&rnd=808016309 | 0 | 245 |
| http://c.cnzz.com/core.php?web_id=2918556&t=z | 865000 | 2263 |
| http://c.cnzz.com/core.php?web_id=2918924&t=z | 867000 | 1282 |
| http://bdimg.share.baidu.com/static/js/bds_s_v2.js?cdnversion=441183 | 1800000 | 10321 |
| http://bdimg.share.baidu.com/static/js/logger.js?cdnversion=441183 | 1800000 | 2733 |
| http://bdimg.share.baidu.com/static/css/bdsstyle.css?cdnversion=20131219 | 1800000 | 2344 |
| http://bdimg.share.baidu.com/static/js/shell_v2.js?t=7 | 1800000 | 900 |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/images/xiala.png | 3600000 | 1839 |
| http://www.51edu.com/images/hot.gif | 3600000 | 1638 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 | 5400000 | 4743 |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 | 5400000 | 4739 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 86400000 | 90583 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 86400000 | 80130 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 86400000 | 37374 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 86400000 | 32118 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 86400000 | 31853 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 86400000 | 30843 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 86400000 | 30182 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg | 86400000 | 26056 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 86400000 | 14525 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018052159549.jpg | 86400000 | 13166 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/images/top1.jpg | 86400000 | 1773 |
| http://bdimg.share.baidu.com/static/images/r1.gif | 604800000 | 1257 |
Accessibility
Indicates how accessible the page is and highlights opportunities where the page can be made more accessible to users of 51edu.com. This includes details about various page attributes that can be optimized.Navigation
`[accesskey]` values are unique Access keys assist users with focusing on different parts of the page. Each access key should be unique for proper navigation.
The page contains a heading, skip link, or landmark region It is advised to provide ways to bypass repetitive content, allowing users to navigate the page efficiently.
No element has a `[tabindex]` value greater than 0 Although technically valid, a tabindex value greater than 0 often creates frustrating experiences for users who rely on assistive technologies.
ARIA
`[aria-*]` attributes match their roles Avoid mismatching 'aria-*' attributes and their 'role' value, as it invalidates the attribute.
`[role]`s have all required `[aria-*]` attributes Some ARIA roles have required 'aria-*' attributes, which provide essential information about state and functionality.
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children. Some ARIA parent roles cannot perform their intended functions if specific child roles are not used.
`[role]`s are contained by their required parent element Some ARIA child roles cannot perform their intended functions if specific parent roles are not used.
`[role]` values are valid All ARIA roles require valid values to perform their intended functions.
`[aria-*]` attributes have valid values ARIA attributes cannot be interpreted with invalid values when used by screen readers and other assistive technologies.
`[aria-*]` attributes are valid and not misspelled ARIA attributes cannot be interpreted with invalid names when used by screen readers and other assistive technologies.
Audio and video
`<audio>` elements contain a `<track>` element with `[kind="captions"]` 51edu.com may provide assistance to deaf or hearing-impaired users with captions on audio elements.
`<video>` elements contain a `<track>` element with `[kind="captions"]` 51edu.com may provide assistance to deaf or hearing-impaired users with captions on videos.
`<video>` elements contain a `<track>` element with `[kind="description"]` 51edu.com may provide relevant information that dialogue cannot, by using audio descriptions.
Names and labels
Buttons have an accessible name Buttons become unusable as they are announced simply as "button" when the button does not have an accessible name, when used by screen readers and other assistive technologies.
Document has a `<title>` element Search engines, screen reader users and other assistive technology users rely on the title to provide an overview of the page and to help determine if the page is relevant to their search.
`<frame>` or `<iframe>` elements have a title Screen reader users and other assistive technology users rely on frame titles to describe the contents of frames.
`<input type="image">` elements have `[alt]` text Input buttons with alternative text assist screen readers and other assistive technology users to understand its purpose.
Form elements have associated labels Screen readers and other assistive technologies rely on labels to properly announce form controls.
`<object>` elements have `[alt]` text It is advised that alt text is used on '<object>' elements in order to provide meaning to screen reader and other assistive technology users, as these technologies are unable to translate non-text content.
Tables and lists
`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>` or `<template>` elements. Screen readers and other assistive technologies may produce poor and inaccurate output when definition lists are not properly marked up.
Definition list items are wrapped in `<dl>` elements In order for screen readers and other assistive technologies to properly announce definition list items ('<dt>' and '<dd>'), they must be wrapped in parent a '<dl>' element.
Presentational `<table>` elements avoid using `<th>`, `<caption>` or the `[summary]` attribute. It is advised to not include data elements in tables which are used for layout purposes, as it may create confusion for screen reader and other assistive technology users.
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements In order for screen readers to announce list items, ensure that list items ('<li>') are contained within parent '<ul>' or '<ol>' tags.
Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table. Screen readers and other assistive technologies have features to make navigating tables easier. Ensure that '<td>' cells using the headers attribute only refer to other cells in the same table, to improve screen reader user experience.
`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe. Screen readers and other assistive technologies have features to make navigating tables easier. Ensure that table headers refer to some set of cells, to improve screen reader user experience.
Best practices
`[id]` attributes on the page are unique It is advised to keep all id attributes unique in order to prevent instances from being overlooked by screen readers and other assistive technologies.
The document does not use `<meta http-equiv="refresh">` Pages that refresh automatically cause a poor user experience as focus is directed back to the top of the page unexpectedly.
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5. For users with low vision who rely on screen magnification, ensure that zooming is not disabled.
Internationalization and localization
`<html>` element has a valid value for its `[lang]` attribute Specify a valid BCP 47 language in order to help screen readers and other assistive technologies announce text properly.
`[lang]` attributes have a valid value Specify a valid BCP 47 language on elements in order to help screen readers and other assistive technologies announce text properly.
Contrast
Background and foreground colors do not have a sufficient contrast ratio. Many (if not most) users find low-contrast text difficult or impossible to read.
| Failing Elements |
|---|
Internationalization and localization
`<html>` element does not have a `[lang]` attribute It is advised to provide a lang attribute so that screen readers and other assistive technologies are guaranteed to announce the page's text correctly. When not provided, the user's default language setting will be used which may cause inaccuracies.
| Failing Elements |
|---|
Names and labels
Image elements do not have `[alt]` attributes Provide short and descriptive alternative text where possible on informative elements.
| Failing Elements |
|---|
Tables and lists
Lists do not contain only `<li>` elements and script supporting elements (`<script>` and `<template>`). Use proper list structure to aid screen readers and other assistive technologies.
| Failing Elements |
|---|
Manual Checks
The page has a logical tab order The visual layout should be logical in its tab order and users cannot focus elements that are offscreen.
Interactive controls are keyboard focusable Ensure that custom interactive controls are keyboard focusable and that a focus indicator is displayed.
Interactive elements indicate their purpose and state Ensure that interactive elements (such as links and buttons) are distinguishable from non-interactive elements and that they indicate their state.
The user's focus is directed to new content added to the page When new content (such as a dialogue) is added to the page, the user's focus should be directed to it.
User focus is not accidentally trapped in a region Avoid focus being accidentally trapped when a user tabs in and out of controls or regions on page.
Custom controls have associated labels Ensure that custom interactive controls have associated labels, which are provided by aria-label and aria-labelledby attributes.
Custom controls have ARIA roles Ensure that all custom interactive controls have appropriate ARIA roles.
Visual order on the page follows DOM order Ensure that the DOM order matches with the page's visual order, in order to improve navigation for screen readers and other assistive technologies.
Offscreen content is hidden from assistive technology Ensure that offscreen content is hidden through the use of "display:none" styling or the aria-hidden attribute.
Headings don't skip levels Ensure that headings create an outline for the page and that heading levels are not skipped.
HTML5 landmark elements are used to improve navigation Elements such as <main> and <nav> are recommended as they are used by screen readers and other assistive technologies to improve keyboard navigation.
Best Practices
Indicates the recommended, best practices currently in place on the page and highlights the best practices that 51edu.com should incorporate. This includes practices such as protecting pages with HTTPS.Other
Avoids Application Cache Application cache is deprecated and is no longer recommended.
Uses passive listeners to improve scrolling performance Improve the page's scroll performance by marking touch and wheel event listeners as 'passive'.
Avoids requesting the geolocation permission on page load When requesting a user's location, provide context or consider tying the request to a user action to avoid confusion and mistrust from users.
Detected JavaScript libraries Below is a list of all front-end JavaScript libraries that were detected on the page.
| Name | Version |
|---|---|
| jQuery | 1.11.3 |
| jQuery (Fast path) |
Avoids requesting the notification permission on page load When requesting permission to send notifications, provide context or consider tying the request to a user action to avoid confusion and mistrust from users.
Avoids deprecated APIs Avoid deprecated APIs which will eventually be removed the browser.
Allows users to paste into password fields Ensure that password inputs may be pasted into to aid in the user's ability to use password managers and improve security.
Displays images with correct aspect ratio Ensure that image display dimensions match their natural aspect ratio.
Other
Does not use HTTPS — 41 insecure requests found Ensure that all pages are protected with HTTPS (including those that do not handle sensitive data) as HTTPS prevents tampering and passive listening on communications between the app and its users. Additionally, HTTPS is a prerequisite for HTTP/2 and many new web platform APIs.
| Insecure URL |
|---|
| http://51edu.com/ |
| http://www.51edu.com/ |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js |
| http://www.51edu.com/images/logob.png |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/images/xiala.png |
| http://www.51edu.com/images/new.gif |
| http://www.51edu.com/images/hot.gif |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg |
| http://cms.51edu.com/uploadfile/2019/1018/20191018052159549.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg |
| http://adm.baidu.com/img/vip_1.gif |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/com.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/images/top1.jpg |
| http://c.cnzz.com/core.php?web_id=2918556&t=z |
| http://hzs19.cnzz.com/stat.htm?id=2918556&r=&lg=en-us&ntime=none&cnzz_eid=535619890-1588250431-&showp=800x600&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb66d55e4b-05abe1b4812fc9-6d274b2b-75300-171cb66d55f253&h=1&rnd=197108804 |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=133339236 |
| http://pcookie.cnzz.com/app.gif?&cna=18gxF8skXjgCAUPNiX8gI1a1 |
| http://c.cnzz.com/core.php?web_id=2918924&t=z |
| http://hzs19.cnzz.com/stat.htm?id=2918924&r=&lg=en-us&ntime=none&cnzz_eid=976571655-1588255447-&showp=800x600&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb66d55e4b-05abe1b4812fc9-6d274b2b-75300-171cb66d55f253&h=1&rnd=808016309 |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=83401928 |
| http://hm.baidu.com/h.js?f23a13a09954dada8fad3e0691dfcf0f |
| http://share.baidu.com/static/js/shell_v2.js?t=7 |
| http://bdimg.share.baidu.com/static/js/shell_v2.js?t=7 |
| http://bdimg.share.baidu.com/static/js/logger.js?cdnversion=441183 |
| http://bdimg.share.baidu.com/static/js/bds_s_v2.js?cdnversion=441183 |
| http://bdimg.share.baidu.com/static/css/bdsstyle.css?cdnversion=20131219 |
| http://bdimg.share.baidu.com/static/images/r1.gif |
| http://nsclick.baidu.com/v.gif?pid=307&type=3071&sc=1350,3489,800,600&desturl=&apitype=1&linkid=k9muae565v9&velo_load=1753&velo_cssload=581&velo_jsLoad=1197&cite_uid=10026&cite_type=4&cite_mini=1 |
Uses `document.write()` Avoid or limit the use of external scripts that are dynamically injected via 'document.write()' as users on slow connections will be delayed by tens of seconds.
| URL | Location |
|---|---|
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 | line: 16 |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 | line: 17 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 | line: 16 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 | line: 17 |
| http://www.51edu.com/ | line: 997 |
Links to cross-origin destinations are unsafe Improve performance and prevent security vulnerabilities by adding rel="noopener" and rel="noreferrer" to external links.
| URL | Target | Rel |
|---|---|---|
| http://so.51edu.com/ | _blank | |
| http://m.51edu.com/ | _blank | |
| http://www.keleliuxue.com/ | _blank | |
| http://www.liumeitong.com/ | _blank | |
| http://www.liumeitong.com/ | _blank | |
| http://www.liumeitong.com/ | _blank | |
| http://www.hjenglish.com/ | _blank | |
| http://www.kekenet.com/ | _blank | |
| http://www.zhongkao.com/ | _blank | |
| http://www.61ertong.com/ | _blank | |
| http://www.ichacha.net/ | _blank | |
| http://www.xuexifangfa.com/ | _blank | |
| http://www.1010jiajiao.com/ | _blank | |
| http://www.chinatat.com/ | _blank | |
| http://www.iliyu.com/ | _blank | |
| http://www.wangxiao.cn/ | _blank | |
| http://www.jiajiaoban.com/ | _blank | |
| http://www.qqbaobao.com/ | _blank | |
| http://www.babytree.com/ | _blank | |
| http://www.kuakao.com/ | _blank | |
| http://www.etest8.com/ | _blank | |
| https://www.cnzz.com/stat/website.php?web_id=2918556 | _blank | |
| https://www.cnzz.com/stat/website.php?web_id=2918924 | _blank |
Page lacks the HTML doctype, thus triggering quirks-mode Ensure a doctype is specified to prevent the browser from switching to quirks-mode.
Includes front-end JavaScript libraries with known security vulnerabilities — 2 vulnerabilities detected Ensure that the use of third-party scripts is minimal and that only trusted third-party scripts are used as some may contain known security vulnerabilities which may be exploited by attackers.
| Library Version | Vulnerability Count | Highest Severity |
|---|---|---|
| 2 | Medium |
Browser errors were logged to the console Below is a list of all errors logged to the console, which indicate unresolved problems on the site.
| URL | Description |
|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js | Failed to load resource: net::ERR_TIMED_OUT |
| http://www.51edu.com/images/new.gif | Failed to load resource: net::ERR_TIMED_OUT |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg | Failed to load resource: net::ERR_TIMED_OUT |
| http://adm.baidu.com/img/vip_1.gif | Failed to load resource: net::ERR_TIMED_OUT |
| http://www.51edu.com/images/logob.png | Failed to load resource: net::ERR_TIMED_OUT |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg | Failed to load resource: net::ERR_TIMED_OUT |
| http://www.51edu.com/ | ReferenceError: Qfast is not defined
at http://www.51edu.com/:879:2 |
SEO
Indicates how well the page is optimized for ranking in search engines and highlights Search Engine Optimization (SEO) opportunities for 51edu.com. This includes optimizations such as providing meta data.Content Best Practices
Document has a `<title>` element Search engines, screen reader users and other assistive technology users rely on the title to provide an overview of the page and to help determine if the page is relevant to their search.
Document has a meta description Meta descriptions may be used by search engines when displaying a link to the page and should concisely summarize the page's content.
Links have descriptive text Make use of descriptive link text to assist search engines in understanding the content.
Document has a valid `hreflang` Search engines can be instructed to list specific versions of a page for a given language or region through the use of hreflang links.
Document has a valid `rel=canonical` Search engines can be suggested which URL should be shown in search results through the use of canonical links.
Document avoids plugins The content of plugins cannot be indexed by search engines and many devices either restrict or do not support them.
Crawling and Indexing
Page has successful HTTP status code Avoid pages with unsuccessful HTTP status codes as they may not be indexed by search engines.
Page isn’t blocked from indexing Pages that cannot be crawled by search engines cannot be indexed or included in their search results. Ensure that search engines have permission to crawl all pages that should be indexed.
robots.txt is valid Malformed robots.txt files prevent crawlers from understanding how a site wants to be crawled or indexed, which can be devastating to SEO.
Mobile Friendly
Document uses legible font sizes Font sizes of 12px or less are too small to most mobile users without user gestures and further action. Aim for more than 60% of page text to use font sizes greater than 12px.
Tap targets are sized appropriately Interactive elements (such as buttons and links) should be appropriately spaced, sized and easy enough to select or tap with regard to their surrounding elements.
Mobile Friendly
Does not have a `<meta name="viewport">` tag with `width` or `initial-scale` It is advised to use a '<meta name="viewport">' tag for the optimization of 51edu.com on mobile screens.
Content Best Practices
Manual Checks
Structured data is valid Structured data can be validated through the use of the Structured Data Testing Tool and the Structured Data Linter.
Progressive Web App
Indicates how valid the aspects of a Progressive Web App (PWA) are for the page and highlights opportunities to enable/improve the PWA of 51edu.com. This includes details about web app manifests.Fast and reliable
Page load is fast enough on mobile networks Ensure that the page loads fast enough over a cellular network, to ensure good mobile user experience.
PWA Optimized
Content is sized correctly for the viewport Ensure that the width of the app's content matches the width of the viewport, otherwise the app might not be optimized for mobile screens.
Contains some content when JavaScript is not available Apps should display alternative content for when JavaScript is disabled.
Fast and reliable
Current page does not respond with a 200 when offline In order for Progressive Web Apps to be made available offline, ensure that the app is using a service worker.
`start_url` does not respond with a 200 when offline Consider using a service worker for Progressive Web Apps to ensure greater reliability for the user, in the case of poor network conditions.
Installable
Does not use HTTPS — 41 insecure requests found Ensure that all pages are protected with HTTPS (including those that do not handle sensitive data) as HTTPS prevents tampering and passive listening on communications between the app and its users. Additionally, HTTPS is a prerequisite for HTTP/2 and many new web platform APIs.
| Insecure URL |
|---|
| http://51edu.com/ |
| http://www.51edu.com/ |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js |
| http://www.51edu.com/images/logob.png |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/images/xiala.png |
| http://www.51edu.com/images/new.gif |
| http://www.51edu.com/images/hot.gif |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg |
| http://cms.51edu.com/uploadfile/2019/1018/20191018052159549.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg |
| http://adm.baidu.com/img/vip_1.gif |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/com.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/images/top1.jpg |
| http://c.cnzz.com/core.php?web_id=2918556&t=z |
| http://hzs19.cnzz.com/stat.htm?id=2918556&r=&lg=en-us&ntime=none&cnzz_eid=535619890-1588250431-&showp=800x600&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb66d55e4b-05abe1b4812fc9-6d274b2b-75300-171cb66d55f253&h=1&rnd=197108804 |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=133339236 |
| http://pcookie.cnzz.com/app.gif?&cna=18gxF8skXjgCAUPNiX8gI1a1 |
| http://c.cnzz.com/core.php?web_id=2918924&t=z |
| http://hzs19.cnzz.com/stat.htm?id=2918924&r=&lg=en-us&ntime=none&cnzz_eid=976571655-1588255447-&showp=800x600&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb66d55e4b-05abe1b4812fc9-6d274b2b-75300-171cb66d55f253&h=1&rnd=808016309 |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=83401928 |
| http://hm.baidu.com/h.js?f23a13a09954dada8fad3e0691dfcf0f |
| http://share.baidu.com/static/js/shell_v2.js?t=7 |
| http://bdimg.share.baidu.com/static/js/shell_v2.js?t=7 |
| http://bdimg.share.baidu.com/static/js/logger.js?cdnversion=441183 |
| http://bdimg.share.baidu.com/static/js/bds_s_v2.js?cdnversion=441183 |
| http://bdimg.share.baidu.com/static/css/bdsstyle.css?cdnversion=20131219 |
| http://bdimg.share.baidu.com/static/images/r1.gif |
| http://nsclick.baidu.com/v.gif?pid=307&type=3071&sc=1350,3489,800,600&desturl=&apitype=1&linkid=k9muae565v9&velo_load=1753&velo_cssload=581&velo_jsLoad=1197&cite_uid=10026&cite_type=4&cite_mini=1 |
Does not register a service worker that controls page and `start_url` A service worker is used to provide Progressive Web Apps the use of features such as working offline, the ability for the app to be added to the homescreen as well as push notifications.
Web app manifest does not meet the installability requirements User engagement may be increased by leveraging the browsers ability to proactively prompt users to add the app to their homescreen.
View Data
PWA Optimized
Does not redirect HTTP traffic to HTTPS It is advised to redirect all HTTP traffic to HTTPS, in order to enable secure web features for all users.
Is not configured for a custom splash screen Themed splash screens ensure a high-quality user experience at launch for app users.
View Data
Does not set a theme color for the address bar. A theme may be applied to the browser address bar, which ideally can be made to match the site.
View Data
Does not have a `<meta name="viewport">` tag with `width` or `initial-scale` It is advised to use a '<meta name="viewport">' tag for the optimization of 51edu.com on mobile screens.
Does not provide a valid `apple-touch-icon` iOS users of Progressive Web Apps will benefit from an apple touch icon, which can be defined with 'apple-touch-icon', which must point to a non-transparent 192px (or 180px) square PNG.
Manual Checks
Site works cross-browser Ensure that the Progressive Web App works correctly across every major browser.
Page transitions don't feel like they block on the network Users perceive apps with responsive, snappy transitions as higher peforming and ensures a great user experience, even on a slow network.
Each page has a URL Ensure that all pages are deep linkable via URL. They should also be unique for the purpose of shareability on social media.
Avg. (All Categories)
Performance
Accessibility
Best Practices
SEO
0–49 (Fail) 50–89 (Average) 90–100 (Pass)
URL: http://www.51edu.com
Updated: 30th April, 2020
4.45 seconds
First Contentful Paint (FCP)
0.31 seconds
First Input Delay (FID) Simulate loading on mobile
Performance
Indicates how well the page is performing and highlights opportunities where performance may be improved for 51edu.com. This includes details about optimizing page load times which can result in a better user experience.Other
Estimated Input Latency — 10 ms The time taken for the page to respond to user input (during the busiest 5 second window of page load). Users are likely to perceive 51edu.com as laggy when the latency is higher than 0.05 seconds.
Total Blocking Time — 130 ms The total blocking time is the sum of all time periods between First Contentful Paint and Time to Interactive (when task length exceeded 50ms).
Network Requests Below is a list of network requests that were made during page load.
| URL | Start Time (Ms) | End Time (Ms) | Transfer Size (Bytes) | Resource Size (Bytes) | Status Code | MIME Type | Resource Type |
|---|---|---|---|---|---|---|---|
| http://51edu.com/ | 0 | 1632.5449999422 | 257 | 0 | 301 | text/html | |
| http://www.51edu.com/ | 1633.3979999181 | 2736.6039999761 | 70196 | 69660 | 200 | text/html | Document |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 2754.8049998004 | 3001.2619998306 | 14518 | 13864 | 200 | text/css | Stylesheet |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 2755.1059999969 | 10403.418999864 | 94289 | 93682 | 200 | application/x-javascript | Script |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js | 2755.2699998487 | 4561.8839999661 | 36304 | 35705 | 200 | application/x-javascript | Script |
| http://www.51edu.com/images/logob.png | 2755.4459997918 | 3306.8130000029 | 11431 | 10772 | 200 | image/png | Image |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/images/xiala.png | 2755.5619999766 | 3026.8199997954 | 1832 | 1183 | 200 | image/png | Image |
| http://www.51edu.com/images/new.gif | 3792.4739997834 | 4066.6939998046 | 1025 | 392 | 200 | image/gif | Image |
| http://www.51edu.com/images/hot.gif | 4067.7759998944 | 4343.2349998038 | 1633 | 999 | 200 | image/gif | Image |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 4344.5509998128 | 5547.9160000104 | 37374 | 53429 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 4569.8629999533 | 5767.7549999207 | 30182 | 47438 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg | 5549.677999923 | 6749.3729998823 | 36025 | 54700 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/1018/20191018052159549.jpg | 5769.5269999094 | 6069.2669998389 | 13166 | 14701 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 6071.3380000088 | 8648.7669998314 | 90583 | 105225 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 6750.8709998801 | 9162.2239998542 | 80130 | 92165 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 8650.3639998846 | 9866.522999946 | 32118 | 32889 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg | 9163.7209998444 | 9768.8689997885 | 30408 | 40065 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 9771.3379999623 | 16050.992999924 | 31853 | 41234 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 9867.7579998039 | 10169.684999855 | 30843 | 40897 | 200 | image/jpeg | Image |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg | 10170.963999815 | 10767.037999816 | 26056 | 35679 | 200 | image/jpeg | Image |
| http://adm.baidu.com/img/vip_1.gif | 10443.944999948 | 11074.725999963 | 207 | 0 | 302 | text/html | |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 | 3027.9029998928 | 3277.0109998528 | 4724 | 11794 | 200 | application/javascript | Script |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 | 3278.333999915 | 3524.7859999072 | 4727 | 11794 | 200 | application/javascript | Script |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 3307.8719999176 | 4568.4699998237 | 96555 | 95957 | 200 | application/x-javascript | Script |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/com.js | 3526.1519998312 | 3791.2779999897 | 1774 | 1172 | 200 | application/x-javascript | Script |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/images/top1.jpg | 10452.255999902 | 11346.741999965 | 1790 | 1123 | 200 | image/jpeg | Image |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/js/terminator2.2.min.js | 10752.417000011 | 11287.837999873 | 18240 | 17643 | 200 | application/x-javascript | Script |
| http://c.cnzz.com/core.php?web_id=2918556&t=z | 10824.769999832 | 11278.478999855 | 2241 | 3085 | 200 | application/javascript | Script |
| http://hzs19.cnzz.com/stat.htm?id=2918556&r=&lg=en-us&ntime=none&cnzz_eid=1658854154-1588250431-&showp=412x660&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb67d618108-026952e732a39c-62703f3e-42630-171cb67d619290&h=1&rnd=565558326 | 10829.481999855 | 13506.404999876 | 245 | 2 | 200 | text/html | Image |
| https://ssp.baidu.com/ | 11074.725999963 | 13575.459999964 | 0 | 0 | -1 | Image | |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=2044831164 | 11282.419999829 | 11425.00999989 | 605 | 0 | 302 | image/gif | |
| http://c.cnzz.com/core.php?web_id=2918924&t=z | 11289.833999937 | 13707.374999998 | 1258 | 969 | 200 | application/javascript | Script |
| http://hzs19.cnzz.com/stat.htm?id=2918924&r=&lg=en-us&ntime=none&cnzz_eid=1434899540-1588255447-&showp=412x660&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb67d618108-026952e732a39c-62703f3e-42630-171cb67d619290&h=1&rnd=288746863 | 11290.504999924 | 12682.906999951 | 245 | 2 | 200 | text/html | Image |
| http://pcookie.cnzz.com/app.gif?&cna=GMkxF+xVlBYCAUPNiX+o6bvm | 11425.222999882 | 12004.546999931 | 420 | 43 | 200 | image/gif | Image |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=677751253 | 13710.003999993 | 13855.335999979 | 495 | 0 | 302 | image/gif | |
| http://hm.baidu.com/h.js?f23a13a09954dada8fad3e0691dfcf0f | 13710.88899998 | 14420.646999963 | 14801 | 40900 | 200 | application/javascript | Script |
| http://pcookie.cnzz.com/app.gif?&cna=GMkxF+xVlBYCAUPNiX+o6bvm | 13855.527999811 | 14603.427999886 | 420 | 43 | 200 | image/gif | Image |
| https://hm.baidu.com/hm.gif?cc=1&ck=1&cl=24-bit&ds=412x660&vl=1923&et=0&ja=0&ln=en-us&lo=0&rnd=1520686657&si=f23a13a09954dada8fad3e0691dfcf0f&v=1.2.74&lv=1&sn=14791&r=0&ww=1200&ct=!!&tt=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0 | 14446.301999968 | 14761.495999992 | 299 | 43 | 200 | image/gif | Image |
| http://share.baidu.com/static/js/shell_v2.js?t=7 | 14446.516999975 | 15066.927999957 | 148 | 0 | 500 | text/plain | Script |
Network Round Trip Times — 0 ms High Network RTT (Round Trip Times) can have a large impact on performance. Providing servers geographically closer to the user could improve performance.
Server Backend Latencies — 0 ms High server latencies indicate the server is overloaded or has a poor backend performance.
Tasks Below is a list of the top-level main thread tasks that executed during page load.
| Start Time (Ms) | End Time (Ms) |
|---|---|
| 2763.725 | 6.82 |
| 2771.247 | 6.028 |
| 10429.646 | 45.497 |
| 10475.289 | 299.568 |
| 10778.298 | 59.803 |
| 10838.198 | 12.173 |
| 11304.247 | 10.944 |
| 11316.072 | 18.846 |
| 14446.499 | 59.362 |
Opportunities
Properly size images Images can slow down the page's load time. 51edu.com should consider serving more appropriate-sized images.
Defer offscreen images — Potential savings of 180 KB Time to Interactive can be slowed down by resources on the page. 51edu.com should consider lazy-loading offscreen and hidden images.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 90583 | 90583 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 80130 | 80130 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018052159549.jpg | 13166 | 13166 |
Minify CSS — Potential savings of 2 KB Cascading Style Sheets (CSS) files can contribute to network payload sizes. 51edu.com should consider minifying CSS files.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 14518 | 2510 |
Minify JavaScript JavaScript (JS) files can contribute to network payload sizes and increase script parse times. 51edu.com should consider minifying JS files.
Remove unused CSS Dead and/or unused rules in Style Sheets (CSS) can contribute to network payload sizes. 51edu.com should consider removing dead rules from style sheets and deferring the loading of CSS not used for above-the-fold content.
Preconnect to required origins Resource hints, such as 'preconnect' or 'dns-prefetch', may assist in establishing early connections to important third-party origins.
Avoid multiple page redirects — Potential savings of 630 ms Redirects can cause additional delays before the page can begin loading. 51edu.com should avoid multiple or unnecessary page redirects.
| URL | Time Spent (Ms) |
|---|---|
| (Start) http://51edu.com/ | 0 |
| http://www.51edu.com/ | 630 |
Preload key requests Key requests can be preloaded by using '<link rel=preload>'. 51edu.com should consider using '<link rel=preload>' to prioritize fetching resources that are currently requested later in page load.
Use video formats for animated content Large GIFs are inefficient for delivering animated content. It is recommended to use MPEG4/WebM videos for animations and PNG/WebP for static images instead of GIF.
Diagnostics
Avoids enormous network payloads — Total size was 800 KB Large network payloads can cost users money and are linked to long load times.
| URL | Size (Bytes) |
|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 96555 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 94289 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 90583 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 80130 |
| http://www.51edu.com/ | 70196 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 37374 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js | 36304 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg | 36025 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 32118 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 31853 |
Avoid chaining critical requests — 8 chains found Below is a list of Critical Request Chains, which shows which resources are loaded with a high priority. 51edu.com should consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
User Timing marks and measures Make use of the User Timing API to measure an app's real-world performance during key user experiences.
JavaScript execution time — 0.5 s JavaScript (JS) execution time can be lowered by reducing the time required for parsing, compiling and executing JS. Delivering smaller JS payloads may help with this.
| URL | Total CPU Time (Ms) | Script Evaluation (Ms) | Script Parse (Ms) |
|---|---|---|---|
| Other | 2206.936 | 136.528 | 3.52 |
| http://hm.baidu.com/h.js?f23a13a09954dada8fad3e0691dfcf0f | 121.552 | 105.876 | 15.676 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 121.024 | 72.024 | 31.132 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 93.624 | 61.336 | 27.896 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js | 61.236 | 56.268 | 4.26 |
All text remains visible during webfont loads Make use of the font-display CSS feature, which will ensure text is user-visible while webfonts are loading.
Keep request counts low and transfer sizes small — 39 requests • 800 KB It is advised to add a budgets.json file in order to set budgets for the quantity and size of page resources.
| Resource Type | Requests | Transfer Size (Bytes) |
|---|---|---|
| Total | 39 | 819417 |
| Image | 22 | 458078 |
| Script | 11 | 275061 |
| Document | 1 | 70196 |
| Stylesheet | 1 | 14518 |
| Other | 4 | 1564 |
| Media | 0 | 0 |
| Font | 0 | 0 |
| Third-party | 15 | 30835 |
Minimize third-party usage — Third-party code blocked the main thread for 20 ms It is advised to either limit, remove or delay the loading of redundant third-party code which may be significantly impacting load performance.
| Third-Party | Size (Bytes) | Main-Thread Blocking Time (Ms) |
|---|---|---|
| 15455 | 16.024 |
Budgets
Performance budget It is advised to keep the quantity and size of all network requests under the targets set by the provided performance budget.
Metrics
First Contentful Paint — 3.3 s The time taken for the first image or text on the page to be rendered.
First Meaningful Paint — 3.3 s The time taken for the primary content of the page to be rendered.
Time to Interactive — 5.3 s The time taken for the page to become fully interactive.
First CPU Idle — 4.4 s The time taken for the page's main thread to be quiet enough to handle input.
Max Potential First Input Delay — 180 ms Users could experience a delay when interacting with the page.
Diagnostics
Avoid an excessive DOM size — 1,204 elements A large DOM (Document Object Model) will increase memory usage, cause longer system calculations as well as costly layout reflows.
| Statistic | Element | Value |
|---|---|---|
| Total DOM Elements | 1,204 | |
| Maximum DOM Depth | 11 | |
| Maximum Child Elements | 30 |
Minimize main-thread work — 2.8 s Main-thread work timing can be lowered by reducing the time required for parsing, compiling and executing JS. Delivering smaller JS payloads may help with this.
| Category | Time Spent (Ms) |
|---|---|
| Style & Layout | 1400.024 |
| Script Evaluation | 568.368 |
| Other | 352.868 |
| Rendering | 275.236 |
| Script Parsing & Compilation | 100.984 |
| Parse HTML & CSS | 68.908 |
Metrics
Speed Index — 18.1 s The time taken for the page contents to be visibly populated.
Opportunities
Eliminate render-blocking resources — Potential savings of 1,560 ms Resources, such as JavaScript and style sheets, can block the first paint of the page. 51edu.com should consider delivering critical JavaScript/style sheets (JS/CSS) inline and deferring all non-critical JS/CSS.
| URL | Size (Bytes) | Potential Savings (Ms) |
|---|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 14518 | 780 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 94289 | 1530 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js | 36304 | 1080 |
Efficiently encode images — Potential savings of 278 KB Unoptimized images can consume more cellular data than what is necessary.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 90583 | 59573 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 80130 | 56774 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 37374 | 27109 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg | 36025 | 25220 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 31853 | 24451 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg | 30408 | 23501 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 30843 | 22916 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 30182 | 20500 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg | 26056 | 18874 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 32118 | 5666 |
Serve images in next-gen formats — Potential savings of 339 KB Image formats like PNG and JPEG have poor compression when compared to other next-gen formats, such as JPEG 200, JPEG XR and WebP.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 90583 | 73223 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 80130 | 68138 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 37374 | 31586 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg | 36025 | 30493 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 31853 | 27779 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg | 30408 | 26464 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 30843 | 26089 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 30182 | 25254 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg | 26056 | 21736 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 32118 | 16144 |
Enable text compression — Potential savings of 216 KB Text-based resources should be served with compression, such as gzip, deflate or brotli.
| URL | Size (Bytes) | Potential Savings (Bytes) |
|---|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 95957 | 62639 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 93682 | 60166 |
| http://www.51edu.com/ | 69660 | 58643 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js | 35705 | 18893 |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/js/terminator2.2.min.js | 17643 | 10707 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 13864 | 10164 |
Reduce server response times (TTFB) — Root document took 1,100 ms Time to First Byte (TTFB) identifies the time at which the server sends a response.
Diagnostics
Serve static assets with an efficient cache policy — 28 resources found 51edu.com can speed up repeat visits by increasing the cache lifetime, which is essentially how long before a cached copy expires.
| URL | Cache TTL (Ms) | Size (Bytes) |
|---|---|---|
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js | 0 | 96555 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js | 0 | 94289 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js | 0 | 36304 |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/js/terminator2.2.min.js | 0 | 18240 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/com.js | 0 | 1774 |
| http://hzs19.cnzz.com/stat.htm?id=2918556&r=&lg=en-us&ntime=none&cnzz_eid=1658854154-1588250431-&showp=412x660&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb67d618108-026952e732a39c-62703f3e-42630-171cb67d619290&h=1&rnd=565558326 | 0 | 245 |
| http://hzs19.cnzz.com/stat.htm?id=2918924&r=&lg=en-us&ntime=none&cnzz_eid=1434899540-1588255447-&showp=412x660&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb67d618108-026952e732a39c-62703f3e-42630-171cb67d619290&h=1&rnd=288746863 | 0 | 245 |
| http://c.cnzz.com/core.php?web_id=2918556&t=z | 815000 | 2241 |
| http://c.cnzz.com/core.php?web_id=2918924&t=z | 817000 | 1258 |
| http://www.51edu.com/images/logob.png | 3600000 | 11431 |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/images/xiala.png | 3600000 | 1832 |
| http://www.51edu.com/images/hot.gif | 3600000 | 1633 |
| http://www.51edu.com/images/new.gif | 3600000 | 1025 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 | 5400000 | 4727 |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 | 5400000 | 4724 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg | 86400000 | 90583 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg | 86400000 | 80130 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg | 86400000 | 37374 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg | 86400000 | 36025 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg | 86400000 | 32118 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg | 86400000 | 31853 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg | 86400000 | 30843 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg | 86400000 | 30408 |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg | 86400000 | 30182 |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg | 86400000 | 26056 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css | 86400000 | 14518 |
| http://cms.51edu.com/uploadfile/2019/1018/20191018052159549.jpg | 86400000 | 13166 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/images/top1.jpg | 86400000 | 1790 |
Other
First Contentful Paint (3G) — 6572 ms The time taken for the first image or text on the page to be rendered while on a 3G network.
Accessibility
Indicates how accessible the page is and highlights opportunities where the page can be made more accessible to users of 51edu.com. This includes details about various page attributes that can be optimized.Navigation
`[accesskey]` values are unique Access keys assist users with focusing on different parts of the page. Each access key should be unique for proper navigation.
The page contains a heading, skip link, or landmark region It is advised to provide ways to bypass repetitive content, allowing users to navigate the page efficiently.
No element has a `[tabindex]` value greater than 0 Although technically valid, a tabindex value greater than 0 often creates frustrating experiences for users who rely on assistive technologies.
ARIA
`[aria-*]` attributes match their roles Avoid mismatching 'aria-*' attributes and their 'role' value, as it invalidates the attribute.
`[role]`s have all required `[aria-*]` attributes Some ARIA roles have required 'aria-*' attributes, which provide essential information about state and functionality.
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children. Some ARIA parent roles cannot perform their intended functions if specific child roles are not used.
`[role]`s are contained by their required parent element Some ARIA child roles cannot perform their intended functions if specific parent roles are not used.
`[role]` values are valid All ARIA roles require valid values to perform their intended functions.
`[aria-*]` attributes have valid values ARIA attributes cannot be interpreted with invalid values when used by screen readers and other assistive technologies.
`[aria-*]` attributes are valid and not misspelled ARIA attributes cannot be interpreted with invalid names when used by screen readers and other assistive technologies.
Audio and video
`<audio>` elements contain a `<track>` element with `[kind="captions"]` 51edu.com may provide assistance to deaf or hearing-impaired users with captions on audio elements.
`<video>` elements contain a `<track>` element with `[kind="captions"]` 51edu.com may provide assistance to deaf or hearing-impaired users with captions on videos.
`<video>` elements contain a `<track>` element with `[kind="description"]` 51edu.com may provide relevant information that dialogue cannot, by using audio descriptions.
Names and labels
Buttons have an accessible name Buttons become unusable as they are announced simply as "button" when the button does not have an accessible name, when used by screen readers and other assistive technologies.
Document has a `<title>` element Search engines, screen reader users and other assistive technology users rely on the title to provide an overview of the page and to help determine if the page is relevant to their search.
`<frame>` or `<iframe>` elements have a title Screen reader users and other assistive technology users rely on frame titles to describe the contents of frames.
`<input type="image">` elements have `[alt]` text Input buttons with alternative text assist screen readers and other assistive technology users to understand its purpose.
Form elements have associated labels Screen readers and other assistive technologies rely on labels to properly announce form controls.
`<object>` elements have `[alt]` text It is advised that alt text is used on '<object>' elements in order to provide meaning to screen reader and other assistive technology users, as these technologies are unable to translate non-text content.
Tables and lists
`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>` or `<template>` elements. Screen readers and other assistive technologies may produce poor and inaccurate output when definition lists are not properly marked up.
Definition list items are wrapped in `<dl>` elements In order for screen readers and other assistive technologies to properly announce definition list items ('<dt>' and '<dd>'), they must be wrapped in parent a '<dl>' element.
Presentational `<table>` elements avoid using `<th>`, `<caption>` or the `[summary]` attribute. It is advised to not include data elements in tables which are used for layout purposes, as it may create confusion for screen reader and other assistive technology users.
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements In order for screen readers to announce list items, ensure that list items ('<li>') are contained within parent '<ul>' or '<ol>' tags.
Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table. Screen readers and other assistive technologies have features to make navigating tables easier. Ensure that '<td>' cells using the headers attribute only refer to other cells in the same table, to improve screen reader user experience.
`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe. Screen readers and other assistive technologies have features to make navigating tables easier. Ensure that table headers refer to some set of cells, to improve screen reader user experience.
Best practices
`[id]` attributes on the page are unique It is advised to keep all id attributes unique in order to prevent instances from being overlooked by screen readers and other assistive technologies.
The document does not use `<meta http-equiv="refresh">` Pages that refresh automatically cause a poor user experience as focus is directed back to the top of the page unexpectedly.
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5. For users with low vision who rely on screen magnification, ensure that zooming is not disabled.
Internationalization and localization
`<html>` element has a valid value for its `[lang]` attribute Specify a valid BCP 47 language in order to help screen readers and other assistive technologies announce text properly.
`[lang]` attributes have a valid value Specify a valid BCP 47 language on elements in order to help screen readers and other assistive technologies announce text properly.
Contrast
Background and foreground colors do not have a sufficient contrast ratio. Many (if not most) users find low-contrast text difficult or impossible to read.
| Failing Elements |
|---|
Internationalization and localization
`<html>` element does not have a `[lang]` attribute It is advised to provide a lang attribute so that screen readers and other assistive technologies are guaranteed to announce the page's text correctly. When not provided, the user's default language setting will be used which may cause inaccuracies.
| Failing Elements |
|---|
Names and labels
Image elements do not have `[alt]` attributes Provide short and descriptive alternative text where possible on informative elements.
| Failing Elements |
|---|
Tables and lists
Lists do not contain only `<li>` elements and script supporting elements (`<script>` and `<template>`). Use proper list structure to aid screen readers and other assistive technologies.
| Failing Elements |
|---|
Manual Checks
The page has a logical tab order The visual layout should be logical in its tab order and users cannot focus elements that are offscreen.
Interactive controls are keyboard focusable Ensure that custom interactive controls are keyboard focusable and that a focus indicator is displayed.
Interactive elements indicate their purpose and state Ensure that interactive elements (such as links and buttons) are distinguishable from non-interactive elements and that they indicate their state.
The user's focus is directed to new content added to the page When new content (such as a dialogue) is added to the page, the user's focus should be directed to it.
User focus is not accidentally trapped in a region Avoid focus being accidentally trapped when a user tabs in and out of controls or regions on page.
Custom controls have associated labels Ensure that custom interactive controls have associated labels, which are provided by aria-label and aria-labelledby attributes.
Custom controls have ARIA roles Ensure that all custom interactive controls have appropriate ARIA roles.
Visual order on the page follows DOM order Ensure that the DOM order matches with the page's visual order, in order to improve navigation for screen readers and other assistive technologies.
Offscreen content is hidden from assistive technology Ensure that offscreen content is hidden through the use of "display:none" styling or the aria-hidden attribute.
Headings don't skip levels Ensure that headings create an outline for the page and that heading levels are not skipped.
HTML5 landmark elements are used to improve navigation Elements such as <main> and <nav> are recommended as they are used by screen readers and other assistive technologies to improve keyboard navigation.
Best Practices
Indicates the recommended, best practices currently in place on the page and highlights the best practices that 51edu.com should incorporate. This includes practices such as protecting pages with HTTPS.Other
Avoids Application Cache Application cache is deprecated and is no longer recommended.
Uses passive listeners to improve scrolling performance Improve the page's scroll performance by marking touch and wheel event listeners as 'passive'.
Avoids requesting the geolocation permission on page load When requesting a user's location, provide context or consider tying the request to a user action to avoid confusion and mistrust from users.
Detected JavaScript libraries Below is a list of all front-end JavaScript libraries that were detected on the page.
| Name | Version |
|---|---|
| jQuery | 1.11.3 |
| jQuery (Fast path) |
Avoids requesting the notification permission on page load When requesting permission to send notifications, provide context or consider tying the request to a user action to avoid confusion and mistrust from users.
Avoids deprecated APIs Avoid deprecated APIs which will eventually be removed the browser.
Allows users to paste into password fields Ensure that password inputs may be pasted into to aid in the user's ability to use password managers and improve security.
Displays images with correct aspect ratio Ensure that image display dimensions match their natural aspect ratio.
Other
Does not use HTTPS — 36 insecure requests found Ensure that all pages are protected with HTTPS (including those that do not handle sensitive data) as HTTPS prevents tampering and passive listening on communications between the app and its users. Additionally, HTTPS is a prerequisite for HTTP/2 and many new web platform APIs.
| Insecure URL |
|---|
| http://51edu.com/ |
| http://www.51edu.com/ |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/css/change.css |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.8.3.min.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/koala.min.1.5.js |
| http://www.51edu.com/images/logob.png |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/images/xiala.png |
| http://www.51edu.com/images/new.gif |
| http://www.51edu.com/images/hot.gif |
| http://cms.51edu.com/uploadfile/2019/0516/20190516040959927.jpg |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041020572.jpg |
| http://cms.51edu.com/uploadfile/2019/0516/20190516041041148.jpg |
| http://cms.51edu.com/uploadfile/2019/1018/20191018052159549.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043425245.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606043518585.jpg |
| http://cms.51edu.com/uploadfile/2019/1018/20191018051239890.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055454345.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606055551913.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042630100.jpg |
| http://cms.51edu.com/uploadfile/2019/0606/20190606042728323.jpg |
| http://adm.baidu.com/img/vip_1.gif |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/jquery-1.11.3.min.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/js/com.js |
| http://img01.51edu.com/templates/51edu/skins/51edu/2013/common/images/top1.jpg |
| http://www.51edu.com/templates/51edu/skins/51edu/2013/common/js/terminator2.2.min.js |
| http://c.cnzz.com/core.php?web_id=2918556&t=z |
| http://hzs19.cnzz.com/stat.htm?id=2918556&r=&lg=en-us&ntime=none&cnzz_eid=1658854154-1588250431-&showp=412x660&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb67d618108-026952e732a39c-62703f3e-42630-171cb67d619290&h=1&rnd=565558326 |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=2044831164 |
| http://c.cnzz.com/core.php?web_id=2918924&t=z |
| http://hzs19.cnzz.com/stat.htm?id=2918924&r=&lg=en-us&ntime=none&cnzz_eid=1434899540-1588255447-&showp=412x660&p=http%3A%2F%2Fwww.51edu.com%2F&t=%E7%B2%BE%E5%93%81%E5%AD%A6%E4%B9%A0%E7%BD%91-%E5%AD%A6%E4%B9%A0%E8%80%83%E8%AF%95%E8%B5%84%E8%AE%AF-%E4%B8%AD%E5%9B%BD%E4%B8%93%E4%B8%9A%E6%95%99%E8%82%B2%E9%97%A8%E6%88%B7%E5%92%8C%E4%BA%92%E5%8A%A8%E8%90%A5%E9%94%80%E5%B9%B3%E5%8F%B0&umuuid=171cb67d618108-026952e732a39c-62703f3e-42630-171cb67d619290&h=1&rnd=288746863 |
| http://pcookie.cnzz.com/app.gif?&cna=GMkxF+xVlBYCAUPNiX+o6bvm |
| http://cnzz.mmstat.com/9.gif?abc=1&rnd=677751253 |
| http://hm.baidu.com/h.js?f23a13a09954dada8fad3e0691dfcf0f |
| http://share.baidu.com/static/js/shell_v2.js?t=7 |
Uses `document.write()` Avoid or limit the use of external scripts that are dynamically injected via 'document.write()' as users on slow connections will be delayed by tens of seconds.
| URL | Location |
|---|---|
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 | line: 16 |
| http://s19.cnzz.com/stat.php?id=2918556&web_id=2918556 | line: 17 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 | line: 16 |
| http://s19.cnzz.com/stat.php?id=2918924&web_id=2918924 | line: 17 |
| http://www.51edu.com/ | line: 997 |
Links to cross-origin destinations are unsafe Improve performance and prevent security vulnerabilities by adding rel="noopener" and rel="noreferrer" to external links.
| URL | Target | Rel |
|---|---|---|
| http://so.51edu.com/ | _blank | |
| http://m.51edu.com/ | _blank | |
| http://www.keleliuxue.com/ | _blank | |
| http://www.liumeitong.com/ | _blank | |
| http://www.liumeitong.com/ | _blank | |
| http://www.liumeitong.com/ | _blank | |
| http://www.hjenglish.com/ | _blank | |
| http://www.kekenet.com/ | _blank | |
| http://www.zhongkao.com/ | _blank | |
| http://www.61ertong.com/ | _blank | |
| http://www.ichacha.net/ | _blank | |
| http://www.xuexifangfa.com/ | _blank | |
| http://www.1010jiajiao.com/ | _blank | |
| http://www.chinatat.com/ | _blank | |
| http://www.iliyu.com/ | _blank | |
| http://www.wangxiao.cn/ | _blank | |
| http://www.jiajiaoban.com/ | _blank | |
| http://www.qqbaobao.com/ | _blank | |
| http://www.babytree.com/ | _blank | |
| http://www.kuakao.com/ | _blank | |
| http://www.etest8.com/ | _blank | |
| https://www.cnzz.com/stat/website.php?web_id=2918556 | _blank | |
| https://www.cnzz.com/stat/website.php?web_id=2918924 | _blank |
Page lacks the HTML doctype, thus triggering quirks-mode Ensure a doctype is specified to prevent the browser from switching to quirks-mode.
Includes front-end JavaScript libraries with known security vulnerabilities — 2 vulnerabilities detected Ensure that the use of third-party scripts is minimal and that only trusted third-party scripts are used as some may contain known security vulnerabilities which may be exploited by attackers.
| Library Version | Vulnerability Count | Highest Severity |
|---|---|---|
| 2 | Medium |
Browser errors were logged to the console Below is a list of all errors logged to the console, which indicate unresolved problems on the site.
| URL | Description |
|---|---|
| https://ssp.baidu.com/ | Failed to load resource: net::ERR_TIMED_OUT |
| http://share.baidu.com/static/js/shell_v2.js?t=7 | Failed to load resource: the server responded with a status of 500 (Internal Server Error) |
SEO
Indicates how well the page is optimized for ranking in search engines and highlights Search Engine Optimization (SEO) opportunities for 51edu.com. This includes optimizations such as providing meta data.Content Best Practices
Document has a `<title>` element Search engines, screen reader users and other assistive technology users rely on the title to provide an overview of the page and to help determine if the page is relevant to their search.
Document has a meta description Meta descriptions may be used by search engines when displaying a link to the page and should concisely summarize the page's content.
Links have descriptive text Make use of descriptive link text to assist search engines in understanding the content.
Document has a valid `hreflang` Search engines can be instructed to list specific versions of a page for a given language or region through the use of hreflang links.
Document has a valid `rel=canonical` Search engines can be suggested which URL should be shown in search results through the use of canonical links.
Document avoids plugins The content of plugins cannot be indexed by search engines and many devices either restrict or do not support them.
Crawling and Indexing
Page has successful HTTP status code Avoid pages with unsuccessful HTTP status codes as they may not be indexed by search engines.
Page isn’t blocked from indexing Pages that cannot be crawled by search engines cannot be indexed or included in their search results. Ensure that search engines have permission to crawl all pages that should be indexed.
robots.txt is valid Malformed robots.txt files prevent crawlers from understanding how a site wants to be crawled or indexed, which can be devastating to SEO.
Mobile Friendly
Does not have a `<meta name="viewport">` tag with `width` or `initial-scale` It is advised to use a '<meta name="viewport">' tag for the optimization of 51edu.com on mobile screens.
Document doesn't use legible font sizes Font sizes of 12px or less are too small to most mobile users without user gestures and further action. Aim for more than 60% of page text to use font sizes greater than 12px.
Tap targets are not sized appropriately Interactive elements (such as buttons and links) should be appropriately spaced, sized and easy enough to select or tap with regard to their surrounding elements.
Content Best Practices
Manual Checks
Structured data is valid Structured data can be validated through the use of the Structured Data Testing Tool and the Structured Data Linter.
Hosting
Server Location
| Server IP Address: | 118.190.77.51 |
| Continent: | Asia |
| Country: | China |
| Region: | |
| City: | |
| Longitude: | 113.7266 |
| Latitude: | 34.7725 |
| Currencies: | CNY |
| Languages: | Mandarin |
Web Hosting Provider
| Name | IP Address |
|---|---|
| Aliyun Computing Co., LTD |
Registration
Domain Registrant
| Private Registration: | No |
| Name: | |
| Organization: |
| Country: | |
| City: | |
| State: | |
| Post Code: | |
| Email: | |
| Phone: |
Note: Registration information is derived from various sources and may be inaccurate.
Domain Registrar
| Name | IP Address |
|---|---|
| Alibaba Cloud Computing (Beijing) Co., Ltd. | 106.11.249.99 |
Security
Visitor Safety
| Mature Content: | Not Likely |
| McAfee WebAdvisor Rating: | Safe |
| WOT Rating: | |
| WOT Trustworthiness: | |
| WOT Child Safety: |
Note: Safety information is not guaranteed.
SSL/TLS Certificate
Technical
DNS Lookup
A Records
| Host | IP Address | Class | TTL |
|---|---|---|---|
| 51edu.com. | 118.190.77.51 | IN | 599 |
NS Records
| Host | Nameserver | Class | TTL |
|---|---|---|---|
| 51edu.com. | dns24.hichina.com. | IN | 21599 |
| 51edu.com. | dns23.hichina.com. | IN | 21599 |
MX Records
| Priority | Host | Server | Class | TTL |
|---|---|---|---|---|
| 10 | 51edu.com. | mxbiz2.qq.com. | IN | 3599 |
| 5 | 51edu.com. | mxbiz1.qq.com. | IN | 3599 |
TXT Records
| Host | Value | Class | TTL |
|---|---|---|---|
| 51edu.com. | v=spf1 | IN | 3599 |
HTTP Response Headers
Whois Lookup
| Created: | 12th May, 2002 |
| Changed: | 6th May, 2019 |
| Expires: | 12th May, 2021 |
| Registrar: | Alibaba Cloud Computing (Beijing) Co., Ltd. |
| Status: | clientTransferProhibited clientUpdateProhibited |
| Nameservers: | dns23.hichina.com dns24.hichina.com |
| Owner State: | Beijing |
| Owner Country: | CN |
| Owner Email: | https://whois.aliyun.com/whois/whoisForm |
| Full Whois: | Domain Name: 51edu.com
Registry Domain ID: 86502811_DOMAIN_COM-VRSN Registrar WHOIS Server: grs-whois.hichina.com Registrar URL: http://whois.aliyun.com Updated Date: 2019-05-06T10:03:16Z Creation Date: 2002-05-12T18:51:11Z Registrar Registration Expiration Date: 2021-05-12T18:51:11Z Registrar: Alibaba Cloud Computing (Beijing) Co., Ltd. Registrar IANA ID: 420 Reseller: Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited Registrant City: Registrant State/Province: Beijing Registrant Country: CN Registrant Email:https://whois.aliyun.com/whois/whoisForm Registry Registrant ID: Not Available From Registry Name Server: DNS23.HICHINA.COM Name Server: DNS24.HICHINA.COM DNSSEC: unsigned Registrar Abuse Contact Email: DomainAbuse@service.aliyun.com Registrar Abuse Contact Phone: +86.95187 URL of the ICANN WHOIS Data Problem Reporting System: http://wdprs.internic.net/ >>>Last update of WHOIS database: 2020-04-30T14:03:52Z <<< For more information on Whois status codes, please visit https://icann.org/epp Important Reminder: Per ICANN 2013RAA`s request, Hichina has modified domain names`whois format of dot com/net/cc/tv, you could refer to section 1.4 posted by ICANN on http://www.icann.org/en/resources/registrars/raa/approved-with-specs-27jun13-en.htm#whois The data in this whois database is provided to you for information purposes only, that is, to assist you in obtaining information about or related to a domain name registration record. We make this information available "as is," and do not guarantee its accuracy. By submitting a whois query, you agree that you will use this data only for lawful purposes and that, under no circumstances will you use this data to: (1)enable high volume, automated, electronic processes that stress or load this whois database system providing you this information; or (2) allow, enable, or otherwise support the transmission of mass unsolicited, commercial advertising or solicitations via direct mail, electronic mail, or by telephone. The compilation, repackaging, dissemination or other use of this data is expressly prohibited without prior written consent from us. We reserve the right to modify these terms at any time. By submitting this query, you agree to abide by these terms.For complete domain details go to:http://whois.aliyun.com/whois/domain/hichina.com |
Nameservers
| Name | IP Address |
|---|---|
| dns23.hichina.com | 47.118.199.200 |
| dns24.hichina.com | 47.118.199.198 |
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