| Avoid slowing down the critical rendering path (avoidRenderBlocking) | The page has 3 blocking requests and 0 in body parser blocking (0 JavaScript and 3 CSS). There are 1 potentially render blocking requests. You need to verify if it is render blocking: https://vi.wikipedia.org/w/load.php?lang=vi&modules=startup&only=scripts&raw=1&skin=vector-2022 | 99 |
| Description: The critical rendering path is what the browser needs to do to start rendering the page. Every file requested inside of the head element will postpone the rendering of the page, because the browser need to do the request. Avoid loading JavaScript synchronously inside of the head (you should not need JavaScript to render the page), request files from the same domain as the main document (to avoid DNS lookups) and inline CSS for really fast rendering and a short rendering path. |
| Offenders: https://vi.wikipedia.org/w/load.php...ia.org/w/load.php |
| Don't scale images in the browser (avoidScalingImages) | The page has 1 image that are scaled more than 100 pixels. It would be better if those images are sent so the browser don't need to scale them. | 90 |
| Description: It's easy to scale images in the browser and make sure they look good in different devices, however that is bad for performance! Scaling images in the browser takes extra CPU time and will hurt performance on mobile. And the user will download extra kilobytes (sometimes megabytes) of data that could be avoided. Don't do that, make sure you create multiple version of the same image server-side and serve the appropriate one. |
| Offenders: https://vi.wikipedia.org/static/images/mobile/copyright/wikipedia-wordmark-en.svg |
| Inline CSS for faster first render (inlineCss) | The page has both inline CSS and CSS requests even though it uses a HTTP/2-ish connection. If you have many users on slow connections, it can be better to only inline the CSS. Run your own tests and check the waterfall graph to see what happens. | 95 |
| Description: In the early days of the Internet, inlining CSS was one of the ugliest things you can do. That has changed if you want your page to start rendering fast for your user. Always inline the critical CSS when you use HTTP/1 and HTTP/2 (avoid doing CSS requests that block rendering) and lazy load and cache the rest of the CSS. It is a little more complicated when using HTTP/2. Does your server support HTTP push? Then maybe that can help. Do you have a lot of users on a slow connection and are serving large chunks of HTML? Then it could be better to use the inline technique, becasue some servers always prioritize HTML content over CSS so the user needs to download the HTML first, before the CSS is downloaded. |
| Avoid CPU Long Tasks (longTasks) | The page has 2 CPU long tasks with the total of 309 ms. The total blocking time is 4 ms and 1 long task before first contentful paint with total time of 255 ms. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. Use Geckoprofiler for Firefox or Chromes tracelog to debug your long tasks. | 60 |
| Description: Long CPU tasks locks the thread. To the user this is commonly visible as a "locked up" page where the browser is unable to respond to user input; this is a major source of bad user experience on the web today. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. To debug you should use the Chrome timeline log and drag/drop it into devtools or use Firefox Geckoprofiler. |
| Offenders: unknownself |
| Avoid doing redirects (assetsRedirects) | The page has 1 redirect. 1 of the redirects are from the base domain, please fix them! | 90 |
| Description: A redirect is one extra step for the user to download the asset. Avoid that if you want to be fast. Redirects are even more of a showstopper on mobile. |
| Offenders: https://vi.wikipedia.org/wiki/Special:CentralAutoLogin/start?type=script |
| Avoid extra requests by setting cache headers (cacheHeaders) | The page has 79 requests that are missing a cache time. Configure a cache time so the browser doesn't need to download them every time. It will save 1.1 MB the next access. | 0 |
| Description: The easiest way to make your page fast is to avoid doing requests to the server. Setting a cache header on your server response will tell the browser that it doesn't need to download the asset again during the configured cache time! Always try to set a cache time if the content doesn't change for every request. |
| Offenders: https://upload.wikimedia.org/wikipedia/commons/thumb/9/95/1000_b%C3%A0i_c%C6%A1_...E1%BA%A3n.svg.png https://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Symbol_star_gold.svg/1...star_gold.svg.png https://upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Vincent_van_Gogh_-_Sel..._%28454045%29.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/c/cd/Vincent_van_Gogh_signa...incent%29.svg.png https://upload.wikimedia.org/wikipedia/commons/thumb/2/21/Speaker_Icon.svg/13px-Speaker_Icon.svg.png https://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Vincent_van_Gogh_Janua...28restored%29.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Theo_van_Gogh_May_1878...28restored%29.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/1/12/Famille_van_Gogh.JPG/2...ille_van_Gogh.JPG https://upload.wikimedia.org/wikipedia/commons/thumb/7/74/VincentVanGoghFoto.jpg...ntVanGoghFoto.jpg 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| Long cache headers is good (cacheHeadersLong) | The page has 5 requests that have a shorter cache time than 30 days (but still a cache time). | 95 |
| Description: Setting a cache header is good. Setting a long cache header (at least 30 days) is even better beacause then it will stay long in the browser cache. But what do you do if that asset change? Rename it and the browser will pick up the new version. |
| Offenders: https://vi.wikipedia.org/w/load.php...ia.org/w/load.php https://vi.wikipedia.org/w/load.php?lang=vi&modules=startup&only=scripts&raw=1&skin=vector-2022 https://vi.wikipedia.org/w/load.php...ia.org/w/load.php https://vi.wikipedia.org/w/load.php?lang=vi&modules=site.styles&only=styles&skin=vector-2022 https://vi.wikipedia.org/w/api.php...dia.org/w/api.php |
| Total image size shouldn't be too big (imageSize) | The page total image size is 1.1 MB. It's really big. Is the page using the right format for the images? Can they be lazy loaded? Are they compressed as good as they can be? Make them smaller by using https://imageoptim.com/. | 50 |
| Description: Avoid having too many large images on the page. The images will not affect the first paint of the page, but it will eat bandwidth for the user. |
| Total JavaScript size shouldn't be too big (javascriptSize) | The total JavaScript transfer size is 400 kB and the uncompressed size is 1.6 MB. This is totally crazy! There is really room for improvement here. | 0 |
| Description: A lot of JavaScript often means you are downloading more than you need. How complex is the page and what can the user do on the page? Do you use multiple JavaScript frameworks? |
| Offenders: |
| Make each CSS response small (optimalCssSize) | https://vi.wikipedia.org/w/load.php?lang=vi&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cmediawiki.page.gallery.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022 size is 23.5 kB (23485) and that is bigger than the limit of 14.5 kB. Try to make the CSS files fit into 14.5 KB. | 90 |
| Description: Make CSS responses small to fit into the magic number TCP window size of 14.5 KB. The browser can then download the CSS faster and that will make the page start rendering earlier. |
| Offenders: |
| Don't use private headers on static content (privateAssets) | The page has 5 requests with private headers. The main page has a private header. It could be right in some cases where the user can be logged in and served specific content. But if your asset is static it should never be private. Make sure that the assets really should be private and only used by one user. Otherwise, make it cacheable for everyone. | 60 |
| Description: If you set private headers on content, that means that the content are specific for that user. Static content should be able to be cached and used by everyone. Avoid setting the cache header to private. |
| Offenders: https://vi.wikipedia.org/wiki/Vincent_van_Gogh https://vi.wikipedia.org/wiki/Special:CentralAutoLogin/start?type=script https://meta.wikimedia.org/w/index.php...a.org/w/index.php https://meta.wikimedia.org/w/index.php...a.org/w/index.php https://login.wikimedia.org/wiki/Special:CentralAutoLogin/checkLoggedIn...gin/checkLoggedIn |
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1.1 sDOM Content Loaded Time 1.033 sFirst Visual Change 1.066 sFirst Contentful Paint 1.072 sLCP <P> 1.072 sVisual Complete 85% 1.100 s
1.2 s
1.3 s
2.1 s
2.5 sLayout Shift 0.00000 2.445 s
2.6 sLayout Shift 0.03330 2.537 smwCentralNoticeBanner 2.586 s
2.7 sLayout Shift 0.02723 2.613 sLargest Image 2.666 sHeading 2.666 s
2.8 sPage Load Time 2.796 s
2.9 sVisual Complete 95% 2.833 s
3.1 s
3.2 s
9.4 s
9.5 s
9.6 s
9.7 s
12.7 s
12.8 s
12.9 s
13 s
13.1 sLast Visual Change 13.033 sVisual Complete 99% 13.033 s
