In May 2021 Microsoft announced that it would be officially retiring Internet Explorer in favor of the Chromium based Microsoft Edge. Usage for the legacy browser had been very low over the past few years, although many websites have still maintained polyfills for the older browser. In fact a number of my clients have recently told me that supporting IE 11 is required by their business, and is still a consideration when adding new features to their sites. I’m sure that the official retirement of Internet Explorer will help numerous organizations embrace modern web features and move on from some expensive polyfills. The official retirement date is June 15, 2022.
Largest Contentful Paint (LCP) is an important metric that measures when the largest element in the browser’s viewport becomes visible. This could be an image, a background image, a poster image for a video, or even a block of text. The metric is measured with the Largest Contentful Paint API, which is supported in Chromium browsers. Optimizing for this metric is critical to end user experience, since it affects their ability to visualize your content.
For the past 10 years, the HTTP Archive has tracked the evolution of the web by archiving the technical details of desktop and mobile homepages. During its early years, the Alexa top million dataset (which was publicly available until 2017) was used to source the list of URLs included in the archive and the number of sites tracked increased from 16K to almost 500K as testing capacity increased. To keep the archive current and include new sites, towards the end of 2018 we started using the Chrome User Experience Report as a source of the URLs to track.
Cookies are used on a lot of websites - 83.9% of the 5.7 million home pages tracked in the HTTP Archive to be specific. They are essentially a name/value pair set by a server and stored in a client’s browser. Sites can store these cookies by using the
document.cookie). On subsequent requests, these cookies are sent to the server in a
Cookie HTTP request header.
Why it occurs, and what is the impact on web performance?
Last year Google announced updates to Chrome that provide a way for developers to control how cross site cookies should work on their sites. This is a good change - as it ultimately improves end user security and privacy by limiting which third parties can read cookies that were set while visiting a different site. It also defeats cross site request forgery attacks. The implementation is fairly simple, and only requires developers to add the SameSite attribute to their cookies.
Back in 2017 the maximum validity lifetime for an HTTPS certificate was set to 825 days, a decision that was widely supported by both browsers and certificate authorities. However, since then there have been multiple unsuccessful attempts at reducing the maximum lifetime to one year. Scott Helme has written about this previously, and his blog post noted that browser vendors unanimously supported this while some certificate authorities objected to it.
According to the HTTP Archive, 84% of HTTPS certificates are using the Subject Alternate Name (SAN) extension, which allows multiple hostnames to be protected by a single certificate. The largest certificate I found in the HTTP Archive contained a whopping 1275 alt-names! During this post we’ll explore why this is a web performance problem, and how you can determine what a reasonable limit would be for your certificates.