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Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
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Detailed Report

Audit breakdown by category with detailed findings.

55

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Performance issues directly impact user engagement and conversion rates.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

RequestCache TTLTransfer Size
www.pku.edu.cn/Uploads/Picture/2026/03/31/s69cb7d1418721.jpg0.0 ms4.1 MiB
www.pku.edu.cn/dat/img/fe7afc17eccc47c499adca9b6c549b4e.jpg0.0 ms2.1 MiB
www.pku.edu.cn/Uploads/Picture/2026/04/02/s69cdfe602790e.jpg0.0 ms2.1 MiB
www.pku.edu.cn/Uploads/Picture/2026/04/17/s69e1c2a2f1019.jpg0.0 ms2.0 MiB
www.pku.edu.cn/dat/img/b2080858ec064a049de34c1ca7eb81e9.png0.0 ms1.9 MiB
www.pku.edu.cn/Uploads/Picture/2026/04/09/s69d759af9ca1b.jpg0.0 ms1.4 MiB
www.pku.edu.cn/Uploads/Picture/2026/02/27/s69a0fec9dcf3b.jpg0.0 ms1.3 MiB
www.pku.edu.cn/dat/img/344b546ab3de42e885101859f6b8ed3b.jpg0.0 ms1.2 MiB
www.pku.edu.cn/Uploads/Picture/2025/09/17/s68ca4cd3c10bb.png0.0 ms697.4 KiB
www.pku.edu.cn/Uploads/Picture/2025/09/22/s68d10dcacb977.jpg0.0 ms567.5 KiB
www.pku.edu.cn/Uploads/Picture/2022/11/02/s6362348db2897.png0.0 ms543.5 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/31/s5e0aa9359ae68.png0.0 ms528.9 KiB
www.pku.edu.cn/Uploads/Picture/2022/11/22/s637cb8c134d80.jpg0.0 ms312.4 KiB
www.pku.edu.cn/Uploads/Picture/2024/11/06/s672b1d5a8248e.jpg0.0 ms232.3 KiB
www.pku.edu.cn/dat/img/3f24a9b3793f4520ae77c2d405badf92.jpg0.0 ms209.0 KiB
www.pku.edu.cn/dat/img/6c7b130555df477791adf7fa0d08e4bf.jpg0.0 ms178.0 KiB
www.pku.edu.cn/dat/img/85d41f2c3212461b885294a7d7d996b3.jpeg0.0 ms166.9 KiB
www.pku.edu.cn/dat/img/15e75d5f2c624be9a8cf1374c317fcf4.jpeg0.0 ms158.7 KiB
www.pku.edu.cn/dat/img/4bdf82f5e8a24fcc9b4e108f570f317a.jpeg0.0 ms155.7 KiB
www.pku.edu.cn/Uploads/Picture/2025/09/15/s68c77d7a66e70.jpg0.0 ms144.7 KiB
www.pku.edu.cn/Public/static/themes/image/pic65.jpg0.0 ms132.5 KiB
www.pku.edu.cn/Uploads/Picture/2025/09/15/s68c789787fad6.jpg0.0 ms125.3 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/26/s5e04176fbbfa3.png0.0 ms50.5 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/20/s5dfc40dc928fb.jpg0.0 ms47.4 KiB
www.pku.edu.cn/Public/static/themes/image/png92.png0.0 ms44.0 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/27/s5e05ab4267239.jpg0.0 ms41.4 KiB
www.pku.edu.cn/Public/static/themes/css/fonts/iconfont.woff0.0 ms39.9 KiB
www.pku.edu.cn/Public/static/themes/js/jquery.js0.0 ms33.1 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/26/s5e04147ee4a83.png0.0 ms28.6 KiB
www.pku.edu.cn/Uploads/Picture/2025/09/08/s68beb6ab0f45e.jpg0.0 ms27.2 KiB
www.pku.edu.cn/Uploads/Picture/2025/09/08/s68beb6392fd51.jpg0.0 ms23.8 KiB
www.pku.edu.cn/Public/static/themes/css/global.css0.0 ms22.8 KiB
www.pku.edu.cn/Public/static/themes/js/jquery.mCustomScrollbar.js0.0 ms22.2 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/05/s5de8762313bab.png0.0 ms18.0 KiB
www.pku.edu.cn/Public/static/themes/js/slick.js0.0 ms15.7 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/03/s5de58ada3ef15.jpg0.0 ms14.7 KiB
www.pku.edu.cn/Public/static/themes/js/iscroll.js0.0 ms12.8 KiB
www.pku.edu.cn/Public/static/themes/css/fix.css0.0 ms11.0 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/03/s5de58b3611072.jpg0.0 ms10.3 KiB
www.pku.edu.cn/Public/static/themes/image/png27.png0.0 ms9.5 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/03/s5de58bbebf671.jpg0.0 ms9.0 KiB
www.pku.edu.cn/Public/static/themes/js/plus/vivus.js0.0 ms8.7 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/18/s5dfa063869f70.jpg0.0 ms7.8 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/03/s5de58b7aaab99.jpg0.0 ms7.1 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/08/s5decd8b95f388.png0.0 ms6.7 KiB
www.pku.edu.cn/Public/static/themes/js/fun.js0.0 ms5.9 KiB
www.pku.edu.cn/Uploads/Picture/2019/12/18/s5dfa062371400.jpg0.0 ms5.0 KiB
www.pku.edu.cn/Public/static/themes/js/plus/jquery.mScroll.js0.0 ms4.8 KiB
www.pku.edu.cn/Public/static/themes/image/png25.png0.0 ms4.4 KiB
/collector/statistic.js?channelId=&channelName=&articleId...0.0 ms3.5 KiB
www.pku.edu.cn/Public/static/themes/image/png26.png0.0 ms2.9 KiB
www.pku.edu.cn/Public/static/themes/js/global.js0.0 ms2.8 KiB
www.pku.edu.cn/Public/static/themes/css/jquery.mCustomScrollbar.css0.0 ms2.7 KiB
www.pku.edu.cn/Public/static/themes/image/png23.png0.0 ms2.4 KiB
www.pku.edu.cn/Public/static/themes/js/homeJson.js0.0 ms2.2 KiB
www.pku.edu.cn/Public/static/themes/js/plus/jquery.imgpreload.js0.0 ms2.0 KiB
www.pku.edu.cn/Public/static/themes/js/plus/jquery.mChange.js0.0 ms1.8 KiB
www.pku.edu.cn/Public/static/themes/image/png5.png0.0 ms1.7 KiB
www.pku.edu.cn/Public/static/themes/js/plus/old/winscreen.js0.0 ms1.7 KiB
www.pku.edu.cn/Public/static/themes/image/png32.svg0.0 ms1.3 KiB
www.pku.edu.cn/Public/static/themes/js/jquery.easing.js0.0 ms1.2 KiB
www.pku.edu.cn/Public/static/themes/image/more1b.svg0.0 ms1.2 KiB
www.pku.edu.cn/Public/static/themes/js/jquery.mousewheel.js0.0 ms1.1 KiB
www.pku.edu.cn/Public/static/themes/css/slick.css0.0 ms848 B
www.pku.edu.cn/Uploads/Picture/2026/03/31/s69cb7d26ba8a5.jpg0.0 ms0 B
www.pku.edu.cn/dat/img/7fc4f699f7bc45f39f49c2d2d292bc1c.jpg0.0 ms0 B

Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]
items: [map[node:map[type:text value:Total] score:0.152955] map[node:map[boundingRect:map[bottom:1190 height:406 left:18 right:394 top:785 width:376] lhId:page-20-DIV nodeLabel:北京大学第五届海军文化节举行 马来西亚拉曼大学校长访问北京大学 韩国友好人士代表团访问北京大学 中俄数学挑战基金研讨会在北京大学举行 2026北京大学管理质效年 path:2,HTML,1,BODY,8,DIV,1,DIV,0,DIV,0,DIV,1,DIV,1,DIV selector:div.home5 > div.block > div.content > div.list snippet:<div class="list"> type:node] score:0.152955]]

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLEst Savings
www.pku.edu.cn/Public/static/themes/css/fonts/iconfont.woff315 ms

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLResource SizeEst Savings
我国科学家近日在光通信和6G领域取得突破性进展 div.slick-track > div.slick-slide > div > div.child
www.pku.edu.cn/Uploads/Picture/2026/03/31/s69cb7d1418721.jpg4.1 MiB2.8 MiB
div.block > div.list > div.item > div.pic div.block > div.list > div.item > div.pic
www.pku.edu.cn/dat/img/b2080858ec064a049de34c1ca7eb81e9.png1.9 MiB1.8 MiB
div.block > div.list > div.item > div.pic div.block > div.list > div.item > div.pic
www.pku.edu.cn/dat/img/344b546ab3de42e885101859f6b8ed3b.jpg1.2 MiB1.1 MiB
北京大学区域与国别研究院建院八周年 div.slick-track > div.slick-slide > div > div.child
www.pku.edu.cn/Uploads/Picture/2026/04/09/s69d759af9ca1b.jpg1.4 MiB1.1 MiB
全球首个靶向整合素的创新核药获批上市 北大为中国核医学70周年献礼 div.slick-track > div.slick-slide > div > div.child
www.pku.edu.cn/Uploads/Picture/2026/04/02/s69cdfe602790e.jpg2.1 MiB820.5 KiB
北京大学校园开放日暨本科招生宣讲会 div.slick-track > div.slick-slide > div > div.child
www.pku.edu.cn/Uploads/Picture/2026/04/17/s69e1c2a2f1019.jpg2.0 MiB747.5 KiB
体育与健康 div.home7 > div.block > div.d2 > div#d2
www.pku.edu.cn/Uploads/Picture/2025/09/17/s68ca4cd3c10bb.png697.2 KiB609.8 KiB
div.ptbox > div.inner > div.pic > div.img div.ptbox > div.inner > div.pic > div.img
www.pku.edu.cn/dat/img/fe7afc17eccc47c499adca9b6c549b4e.jpg2.1 MiB258.2 KiB
div.block > div.list > div.item > div.pic div.block > div.list > div.item > div.pic
www.pku.edu.cn/dat/img/3f24a9b3793f4520ae77c2d405badf92.jpg208.7 KiB181.2 KiB
div.inner > div.l > a > img div.inner > div.l > a > img
www.pku.edu.cn/dat/img/85d41f2c3212461b885294a7d7d996b3.jpeg166.7 KiB161.7 KiB
div.block > div.list > div.item > div.pic div.block > div.list > div.item > div.pic
www.pku.edu.cn/dat/img/6c7b130555df477791adf7fa0d08e4bf.jpg177.7 KiB148.9 KiB
div.pic > div.img > a > img div.pic > div.img > a > img
www.pku.edu.cn/dat/img/15e75d5f2c624be9a8cf1374c317fcf4.jpeg158.4 KiB139.8 KiB
div.inner > div.l > a > img div.inner > div.l > a > img
www.pku.edu.cn/Public/static/themes/image/pic65.jpg132.3 KiB127.8 KiB
div.pic > div.img > a > img div.pic > div.img > a > img
www.pku.edu.cn/dat/img/4bdf82f5e8a24fcc9b4e108f570f317a.jpeg155.4 KiB108.4 KiB
div.item > a > div.pic > ::before div.item > a > div.pic > ::before
www.pku.edu.cn/Public/static/themes/image/png92.png43.8 KiB37.9 KiB
艺术与文化 div.home7 > div.block > div.d2 > div#d1
www.pku.edu.cn/Uploads/Picture/2019/12/20/s5dfc40dc928fb.jpg47.2 KiB34.2 KiB
div.block > div.logo > a > img div.block > div.logo > a > img
www.pku.edu.cn/Uploads/Picture/2019/12/26/s5e04147ee4a83.png28.3 KiB26.9 KiB
校园 · 生活 感受流光溢彩的青春 div.scroll > div.home7 > div.block > div.d1
www.pku.edu.cn/Uploads/Picture/2025/09/15/s68c77d7a66e70.jpg144.4 KiB24.1 KiB
div.part2 > div.logo > a > img div.part2 > div.logo > a > img
www.pku.edu.cn/Uploads/Picture/2019/12/05/s5de8762313bab.png17.7 KiB14.2 KiB
body > div.body_home > div.rr body > div.body_home > div.rr
www.pku.edu.cn/Public/static/themes/image/png27.png9.2 KiB6.9 KiB

Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]
items: [map[duration:1099.214 label:Time to first byte subpart:timeToFirstByte] map[duration:5912.416 label:Element render delay subpart:elementRenderDelay]]
lhId: page-19-DIV
nodeLabel: 北大医学厚道学堂正式成立，首发项目“未来医学教育领航者培养计划”同步启航
path: 2,HTML,1,BODY,8,DIV,1,DIV,0,DIV,0,DIV,1,DIV,0,DIV,1,DIV,3,DIV,0,A,0,DIV,0,DIV
selector: div.item > a > div.text > div.h
snippet: <div class="h">

HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLProtocol
www.pku.edu.cn/http/1.1
www.pku.edu.cn/Public/static/themes/css/jquery.mCustomScrollbar.csshttp/1.1
www.pku.edu.cn/Public/static/themes/css/global.csshttp/1.1
www.pku.edu.cn/Public/static/themes/css/fix.csshttp/1.1
www.pku.edu.cn/Public/static/themes/js/jquery.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/jquery.easing.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/jquery.mousewheel.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/global.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/fun.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/plus/old/winscreen.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/plus/jquery.mChange.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/plus/jquery.mScroll.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/plus/vivus.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/jquery.mCustomScrollbar.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/iscroll.jshttp/1.1
www.pku.edu.cn/Public/static/themes/css/slick.csshttp/1.1
www.pku.edu.cn/Public/static/themes/js/slick.jshttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/26/s5e04147ee4a83.pnghttp/1.1
www.pku.edu.cn/Uploads/Picture/2024/11/06/s672b1d5a8248e.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2025/09/08/s68beb6ab0f45e.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2022/11/02/s6362348db2897.pnghttp/1.1
www.pku.edu.cn/Uploads/Picture/2025/09/15/s68c789787fad6.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2025/09/08/s68beb6392fd51.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2022/11/22/s637cb8c134d80.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2025/09/22/s68d10dcacb977.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/08/s5decd8b95f388.pnghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/26/s5e04176fbbfa3.pnghttp/1.1
www.pku.edu.cn/Public/static/themes/image/pic65.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/27/s5e05ab4267239.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/31/s5e0aa9359ae68.pnghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/05/s5de8762313bab.pnghttp/1.1
www.pku.edu.cn/Public/static/themes/js/homeJson.jshttp/1.1
www.pku.edu.cn/Public/static/themes/js/plus/jquery.imgpreload.jshttp/1.1
www.pku.edu.cn/Uploads/Picture/2026/04/17/s69e1c2a2f1019.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2026/04/09/s69d759af9ca1b.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2026/04/02/s69cdfe602790e.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2026/03/31/s69cb7d26ba8a5.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2026/03/31/s69cb7d1418721.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2026/02/27/s69a0fec9dcf3b.jpghttp/1.1
www.pku.edu.cn/Public/static/themes/image/png27.pnghttp/1.1
www.pku.edu.cn/Public/static/themes/image/png23.pnghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/03/s5de58ada3ef15.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/03/s5de58b3611072.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/03/s5de58b7aaab99.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/03/s5de58bbebf671.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2025/09/15/s68c77d7a66e70.jpghttp/1.1
www.pku.edu.cn/Public/static/themes/image/more1b.svghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/20/s5dfc40dc928fb.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2025/09/17/s68ca4cd3c10bb.pnghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/18/s5dfa062371400.jpghttp/1.1
www.pku.edu.cn/Uploads/Picture/2019/12/18/s5dfa063869f70.jpghttp/1.1
www.pku.edu.cn/Public/static/themes/image/png32.svghttp/1.1
www.pku.edu.cn/Public/static/themes/image/png25.pnghttp/1.1
www.pku.edu.cn/Public/static/themes/image/png26.pnghttp/1.1
www.pku.edu.cn/Public/static/themes/css/fonts/iconfont.woffhttp/1.1
www.pku.edu.cn/Public/static/themes/image/png5.pnghttp/1.1
www.pku.edu.cn/dat/recentList.xmlhttp/1.1
www.pku.edu.cn/dat/recentStatement.xmlhttp/1.1
www.pku.edu.cn/dat/topNews.jsonhttp/1.1
www.pku.edu.cn/dat/imgNews.jsonhttp/1.1
www.pku.edu.cn/dat/teachResearchNews.jsonhttp/1.1
www.pku.edu.cn/dat/mediaPKU.jsonhttp/1.1
www.pku.edu.cn/dat/forumPKU.jsonhttp/1.1
www.pku.edu.cn/dat/pkuPeople.jsonhttp/1.1
www.pku.edu.cn/dat/hotTopics.jsonhttp/1.1
www.pku.edu.cn/dat/img/7fc4f699f7bc45f39f49c2d2d292bc1c.jpghttp/1.1
www.pku.edu.cn/dat/img/fe7afc17eccc47c499adca9b6c549b4e.jpghttp/1.1
www.pku.edu.cn/dat/img/85d41f2c3212461b885294a7d7d996b3.jpeghttp/1.1
www.pku.edu.cn/Public/static/themes/image/png92.pnghttp/1.1
www.pku.edu.cn/dat/img/4bdf82f5e8a24fcc9b4e108f570f317a.jpeghttp/1.1
www.pku.edu.cn/dat/img/15e75d5f2c624be9a8cf1374c317fcf4.jpeghttp/1.1
www.pku.edu.cn/dat/img/344b546ab3de42e885101859f6b8ed3b.jpghttp/1.1
www.pku.edu.cn/dat/img/b2080858ec064a049de34c1ca7eb81e9.pnghttp/1.1
www.pku.edu.cn/dat/img/6c7b130555df477791adf7fa0d08e4bf.jpghttp/1.1
www.pku.edu.cn/dat/img/3f24a9b3793f4520ae77c2d405badf92.jpghttp/1.1

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
value: no origins were preconnected
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates
value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer SizeDuration
www.pku.edu.cn/Public/static/themes/js/plus/old/winscreen.js1.7 KiB199 ms
www.pku.edu.cn/Public/static/themes/js/slick.js15.7 KiB499 ms
www.pku.edu.cn/Public/static/themes/js/jquery.mCustomScrollbar.js22.2 KiB799 ms
www.pku.edu.cn/Public/static/themes/js/iscroll.js12.8 KiB499 ms
www.pku.edu.cn/Public/static/themes/js/plus/vivus.js8.7 KiB499 ms
www.pku.edu.cn/Public/static/themes/js/plus/jquery.mScroll.js4.8 KiB349 ms
www.pku.edu.cn/Public/static/themes/js/plus/jquery.mChange.js1.8 KiB199 ms
www.pku.edu.cn/Public/static/themes/js/jquery.js33.1 KiB1.4 s
www.pku.edu.cn/Public/static/themes/css/global.css22.8 KiB1.1 s
www.pku.edu.cn/Public/static/themes/js/fun.js5.9 KiB349 ms
www.pku.edu.cn/Public/static/themes/js/global.js2.8 KiB199 ms
www.pku.edu.cn/Public/static/themes/js/jquery.mousewheel.js1.1 KiB199 ms
www.pku.edu.cn/Public/static/themes/js/jquery.easing.js1.2 KiB499 ms
www.pku.edu.cn/Public/static/themes/css/slick.css848 B499 ms
www.pku.edu.cn/Public/static/themes/css/fix.css11.0 KiB649 ms
www.pku.edu.cn/Public/static/themes/css/jquery.mCustomScrollbar.css2.7 KiB199 ms

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLS

Why this matters

Performance issues directly impact user engagement and conversion rates.

ElementLayout shift score
北京大学第五届海军文化节举行 马来西亚拉曼大学校长访问北京大学 韩国友好人士代表团访问北京大学 中俄数学挑战基金研讨会在北京大学举行 2026北京大学管理质效年 div.home5 > div.block > div.content > div.list
0.153

Diagnostics

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 50 ms 2.1 KiB
URLTransfer SizeEst Savings
www.pku.edu.cn/Public/static/themes/css/global.css22.8 KiB2.1 KiB

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 150 ms 24.1 KiB
URLTransfer SizeEst Savings
www.pku.edu.cn/Public/static/themes/js/jquery.mCustomScrollbar.js21.8 KiB8.5 KiB
www.pku.edu.cn/Public/static/themes/js/slick.js15.3 KiB6.1 KiB
www.pku.edu.cn/Public/static/themes/js/plus/vivus.js8.4 KiB4.3 KiB
www.pku.edu.cn/Public/static/themes/js/iscroll.js12.4 KiB3.1 KiB
www.pku.edu.cn/Public/static/themes/js/plus/jquery.mScroll.js4.5 KiB2.0 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 100 ms 17.4 KiB
URLTransfer SizeEst Savings
www.pku.edu.cn/Public/static/themes/css/global.css22.5 KiB17.4 KiB

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

CategoryTime Spent
Other4.2 s
Rendering1.7 s
Style & Layout1.7 s
Script Evaluation839 ms
Parse HTML & CSS60 ms
Garbage Collection48 ms
Script Parsing & Compilation46 ms

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer Size
www.pku.edu.cn/Uploads/Picture/2026/03/31/s69cb7d1418721.jpg4.1 MiB
www.pku.edu.cn/dat/img/fe7afc17eccc47c499adca9b6c549b4e.jpg2.1 MiB
www.pku.edu.cn/Uploads/Picture/2026/04/02/s69cdfe602790e.jpg2.1 MiB
www.pku.edu.cn/Uploads/Picture/2026/04/17/s69e1c2a2f1019.jpg2.0 MiB
www.pku.edu.cn/Uploads/Picture/2026/03/31/s69cb7d26ba8a5.jpg2.0 MiB
www.pku.edu.cn/dat/img/b2080858ec064a049de34c1ca7eb81e9.png1.9 MiB
www.pku.edu.cn/Uploads/Picture/2026/04/09/s69d759af9ca1b.jpg1.4 MiB
www.pku.edu.cn/Uploads/Picture/2026/02/27/s69a0fec9dcf3b.jpg1.3 MiB
www.pku.edu.cn/dat/img/344b546ab3de42e885101859f6b8ed3b.jpg1.2 MiB
www.pku.edu.cn/dat/img/7fc4f699f7bc45f39f49c2d2d292bc1c.jpg1.1 MiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
div.pic > div.img > a > img div.pic > div.img > a > img
www.pku.edu.cn/dat/img/15e75d5f2c624be9a8cf1374c317fcf4.jpeg
div.share-box > a.share-item > span.code > img div.share-box > a.share-item > span.code > img
www.pku.edu.cn/Uploads/Picture/2019/12/31/s5e0aa9359ae68.png
div.pic > div.img > a > img div.pic > div.img > a > img
www.pku.edu.cn/dat/img/4bdf82f5e8a24fcc9b4e108f570f317a.jpeg
div.inner > div.l > a > img div.inner > div.l > a > img
www.pku.edu.cn/dat/img/85d41f2c3212461b885294a7d7d996b3.jpeg
div.block > div.logo > a > img div.block > div.logo > a > img
www.pku.edu.cn/Uploads/Picture/2019/12/26/s5e04147ee4a83.png
div.share-box > a.share-item > span.code > img div.share-box > a.share-item > span.code > img
www.pku.edu.cn/Uploads/Picture/2019/12/27/s5e05ab4267239.jpg
div.part2 > div.logo > a > img div.part2 > div.logo > a > img
www.pku.edu.cn/Uploads/Picture/2019/12/05/s5de8762313bab.png
div.nav_mobile > div.logo > a > img div.nav_mobile > div.logo > a > img
www.pku.edu.cn/Uploads/Picture/2019/12/08/s5decd8b95f388.png
div > div.child > a > img._lazyload div > div.child > a > img._lazyload
div > div.child > a > img._lazyload div > div.child > a > img._lazyload
div > div.child > a > img._lazyload div > div.child > a > img._lazyload
div > div.child > a > img._lazyload div > div.child > a > img._lazyload
div > div.child > a > img._lazyload div > div.child > a > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div#slick-slide20 > div > div.child > img._lazyload div#slick-slide20 > div > div.child > img._lazyload
div#slick-slide21 > div > div.child > img._lazyload div#slick-slide21 > div > div.child > img._lazyload
div#slick-slide22 > div > div.child > img._lazyload div#slick-slide22 > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div#slick-slide30 > div > div.child > img._lazyload div#slick-slide30 > div > div.child > img._lazyload
div#slick-slide31 > div > div.child > img._lazyload div#slick-slide31 > div > div.child > img._lazyload
div#slick-slide32 > div > div.child > img._lazyload div#slick-slide32 > div > div.child > img._lazyload
div#slick-slide33 > div > div.child > img._lazyload div#slick-slide33 > div > div.child > img._lazyload
div#slick-slide34 > div > div.child > img._lazyload div#slick-slide34 > div > div.child > img._lazyload
div#slick-slide35 > div > div.child > img._lazyload div#slick-slide35 > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.slick-slide > div > div.child > img._lazyload div.slick-slide > div > div.child > img._lazyload
div.part1 > div.list > div.item > img._lazyload div.part1 > div.list > div.item > img._lazyload
div.part1 > div.list > div.item > img._lazyload div.part1 > div.list > div.item > img._lazyload
div.part1 > div.list > div.item > img._lazyload div.part1 > div.list > div.item > img._lazyload
div.part1 > div.list > div.item > img._lazyload div.part1 > div.list > div.item > img._lazyload

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Max Potential First Input Delay 120 ms
●Document request latency
●Optimize DOM size
●Forced reflow
●Optimize viewport for mobile
●Reduce unused JavaScript
●JavaScript execution time 0.8 s
●Avoid long main-thread tasks 4 long tasks found
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 320 ms
●Server Backend Latencies 50 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Avoid multiple page redirects
●Initial server response time was short Root document took 550 ms
○INP breakdown
○LCP request discovery
○User Timing marks and measures
○Avoid non-composited animations
69

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Internationalization and localization

If a page doesn't specify a `lang` attribute, a screen reader assumes that the page is in the default language that the user chose when setting up the screen reader. If the page isn't actually in the default language, then the screen reader might not announce the page's text correctly. Learn more about the `lang` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html.home html.home

These are opportunities to improve the interpretation of your content by users in different locales.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.inner > div.l > a > img div.inner > div.l > a > img

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.d2 > div.block > div.logo > a div.d2 > div.block > div.logo > a
div#slick-slide00 > div > div.child > a.a1 div#slick-slide00 > div > div.child > a.a1
div#slick-slide00 > div > div.child > a.a2 div#slick-slide00 > div > div.child > a.a2
div.inner > div.pic > div.img > a div.inner > div.pic > div.img > a
div.inner > div.pic > div.img > a div.inner > div.pic > div.img > a
div.block > div.list > div.item > a div.block > div.list > div.item > a
div.block > div.list > div.item > a div.block > div.list > div.item > a
div.block > div.list > div.item > a div.block > div.list > div.item > a
div.block > div.list > div.item > a div.block > div.list > div.item > a
div.text > div.inner > div.l > a div.text > div.inner > div.l > a
div.inner > div.pic > div.img > a div.inner > div.pic > div.img > a
div.inner > div.pic > div.img > a div.inner > div.pic > div.img > a
div.block > div.d2 > div#d1 > a div.block > div.d2 > div#d1 > a
div.block > div.d2 > div#d2 > a div.block > div.d2 > div#d2 > a
div.block > div.d2 > div#d3 > a div.block > div.d2 > div#d3 > a
div.block > div.d4 > div#d4 > a div.block > div.d4 > div#d4 > a
div.block > div.d4 > div#d5 > a div.block > div.d4 > div#d5 > a
div.block > div.d4 > div#d6 > a div.block > div.d4 > div#d6 > a
div.part1 > div.list > div.item > a div.part1 > div.list > div.item > a
div.part1 > div.list > div.item > a div.part1 > div.list > div.item > a
div.part1 > div.list > div.item > a div.part1 > div.list > div.item > a
div.part1 > div.list > div.item > a div.part1 > div.list > div.item > a
div.footer > div.part2 > div.logo > a div.footer > div.part2 > div.logo > a

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Best practices

Disabling zooming is problematic for users with low vision who rely on screen magnification to properly see the contents of a web page. Learn more about the viewport meta tag.

Why this matters

Informational: a Permissions-Policy directive showing feature -> allowed origins.

Source: MDN Permissions-Policy

Failing Elements
head > meta head > meta

Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
新闻 div.part1 > div.nav_foot > div.inner > a
招生 div.part1 > div.nav_foot > div.inner > a
招聘 div.part1 > div.nav_foot > div.inner > a
捐赠 div.part1 > div.nav_foot > div.inner > a
校园地图 div.part1 > div.nav_foot > div.inner > a
校历 div.part1 > div.nav_foot > div.inner > a
燕园特写 div.part1 > div.nav_foot > div.inner > a
未名BBS div.part1 > div.nav_foot > div.inner > a

These items highlight common accessibility best practices.

Navigation

A value greater than 0 implies an explicit navigation ordering. Although technically valid, this often creates frustrating experiences for users who rely on assistive technologies. Learn more about the `tabindex` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
北大 · 要闻 北京大学扎实开展树立和践行正确政绩观学习教育 越南青年“红色研学之旅”之“不忘初心”研学营走进北京大学 世界气象组织秘书长席列斯特·绍罗访问北… body > div.body_b

These are opportunities to improve keyboard navigation in your application.

○Interactive controls are keyboard focusable
○Interactive elements indicate their purpose and state
○The page has a logical tab order
○Visual order on the page follows DOM order
○User focus is not accidentally trapped in a region
○The user's focus is directed to new content added to the page
○HTML5 landmark elements are used to improve navigation
○Offscreen content is hidden from assistive technology
○Custom controls have associated labels
○Custom controls have ARIA roles
●`[aria-*]` attributes match their roles
●`[aria-hidden="true"]` is not present on the document `<body>`
●`[role]`s have all required `[aria-*]` attributes
●`[role]` values are valid
●`[aria-*]` attributes have valid values
●`[aria-*]` attributes are valid and not misspelled
●ARIA attributes are used as specified for the element's role
●`[aria-hidden="true"]` elements do not contain focusable descendents
●Elements use only permitted ARIA attributes
●Background and foreground colors have a sufficient contrast ratio
●Document has a `<title>` element
●Links are distinguishable without relying on color.
●Document has a main landmark.
●Deprecated ARIA roles were not used
●The page contains a heading, skip link, or landmark region
●Identical links have the same purpose.
○`[accesskey]` values are unique
○`button`, `link`, and `menuitem` elements have accessible names
○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
○ARIA input fields have accessible names
○ARIA `meter` elements have accessible names
○ARIA `progressbar` elements have accessible names
○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
○`[role]`s are contained by their required parent element
○Elements with the `role=text` attribute do not have focusable descendents.
○ARIA toggle fields have accessible names
○ARIA `tooltip` elements have accessible names
○ARIA `treeitem` elements have accessible names
○Buttons have an accessible name
○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
○Definition list items are wrapped in `<dl>` elements
○ARIA IDs are unique
○No form fields have multiple labels
○`<frame>` or `<iframe>` elements have a title
○Heading elements appear in a sequentially-descending order
○`<html>` element has a valid value for its `[lang]` attribute
○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
○Input buttons have discernible text.
○`<input type="image">` elements have `[alt]` text
○Form elements have associated labels
○Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
○List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Select elements have associated label elements.
○Skip links are focusable.
○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
○`[lang]` attributes have a valid value
○`<video>` elements contain a `<track>` element with `[kind="captions"]`
○Tables have different content in the summary attribute and `<caption>`.
○All heading elements contain content.
○Uses ARIA roles only on compatible elements
○Image elements do not have `[alt]` attributes that are redundant text.
○Elements with visible text labels have matching accessible names.
○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
○`<td>` elements in a large `<table>` have one or more table headers.
100

Best Practices

●Uses HTTPS
●Avoids deprecated APIs
●Avoids third-party cookies
●Allows users to paste into input fields
●Avoids requesting the geolocation permission on page load
●Avoids requesting the notification permission on page load
●Displays images with correct aspect ratio
●Serves images with appropriate resolution
●Page has the HTML doctype
●Properly defines charset
●No browser errors logged to the console
●No issues in the `Issues` panel in Chrome Devtools
●Ensure CSP is effective against XSS attacks
●Use a strong HSTS policy
●Ensure proper origin isolation with COOP
●Mitigate clickjacking with XFO or CSP
●Mitigate DOM-based XSS with Trusted Types
●Detected JavaScript libraries
●Page has valid source maps
○Redirects HTTP traffic to HTTPS
82

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Crawling and Indexing

Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uncrawlable Link
div.slick-slide > div > div.child > a.a1 div.slick-slide > div > div.child > a.a1
div#slick-slide01 > div > div.child > a.a1 div#slick-slide01 > div > div.child > a.a1
div#slick-slide05 > div > div.child > a.a1 div#slick-slide05 > div > div.child > a.a1
div.slick-slide > div > div.child > a.a1 div.slick-slide > div > div.child > a.a1
div.slick-slide > div > div.child > a.a1 div.slick-slide > div > div.child > a.a1
div.slick-slide > div > div.child > a div.slick-slide > div > div.child > a
div.slick-slide > div > div.child > a div.slick-slide > div > div.child > a
通知公告 div.l > div.title > div.fz40 > a.now
北大声明 div.l > div.title > div.fz40 > a
div#slick-slide30 > div > div.child > a div#slick-slide30 > div > div.child > a
div.slick-slide > div > div.child > a div.slick-slide > div > div.child > a

To appear in search results, crawlers need access to your app.

Content Best Practices

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.inner > div.l > a > img div.inner > div.l > a > img

Format your HTML in a way that enables crawlers to better understand your app’s content.

○Structured data is valid
●Page isn’t blocked from indexing
●Document has a `<title>` element
●Document has a meta description
●Page has successful HTTP status code
●Links have descriptive text
●Document has a valid `hreflang`
○robots.txt is valid
○Document has a valid `rel=canonical`

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