NUMBER OF INTERNET USERS 462 MILLION INDIA 286 MILLION USA 139 MILLION BRAZIL 132 MILLION INDONESIA 118 MILLION JAPAN 104 MILLION RUSSIA 93 MILLION NIGERIA 71 MILLION GERMANY 69 MILLION MEXICO www.internetworldstats.com/top20.htm
signup. BBC loses 10% of users for every additional second in load time. The Trainline reduced latency and customers spent an extra ~$11.5 million a year.
resolution or transparency? Need a large color palette? (+256 colors) YES NO YES NO YES NO developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/image-optimization
resolution or transparency? Need a large color palette? (+256 colors) PNG-8 PNG-24 YES NO YES NO YES NO developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/image-optimization
resolution or transparency? Need a large color palette? (+256 colors) PNG-8 PNG-24 JPEG YES NO YES NO YES NO developers.google.com/web/fundamentals/performance/optimizing-content-efficiency/image-optimization
page that you are currently on, even if that page hasn't expired yet. However, they also go a step further and revalidate all sub-resources on the page — things like images and JavaScript files.
rect.top >= 0 && rect.left >= 0 && rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) && rect.right <= (window.innerWidth || document.documentElement.clientWidth) ); } How to tell if a DOM element is visible in the current viewport? stackoverflow.com/questions/123999/how-to-tell-if-a-dom-element-is-visible-in-the-current-viewport
trigger force layout/reflow return ( rect.top >= 0 && rect.left >= 0 && rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) && rect.right <= (window.innerWidth || document.documentElement.clientWidth) ); } How to tell if a DOM element is visible in the current viewport? stackoverflow.com/questions/123999/how-to-tell-if-a-dom-element-is-visible-in-the-current-viewport
// Process entries // report back for analytics and monitoring // ... }); }); perfObserver.observe({entryTypes: ['longtask']}); - longtask - window.performance.getEntriesByType('longtask')
perfect HTTP/2 push, since it doesn't need to wait for the browser to make the request. However, preloading is drastically simpler and easier to debug. I recommend using it today, as browser support is only going to get better – but do keep an eye on devtools to ensure your pushed items are being used. “
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