A rather geeky/technical weblog, est. 2001, by Bramus
This talk by Patrick Brosset is one of my favorite talks from this year’s CSS Day Conference. How do browsers actually recalculate styles when webpages change? Can the way you write CSS impact the speed of the recalculation process? In this talk, we’ll go through the details of how browser engines react to DOM changes …
:has() in use?
Great post on style invalidation in Blink, written by Byungwoo who implemented :has() in Blink.
@property
Custom properties – even when registered through @property – don’t animate on the compositor.
Harry Roberts takes a look at some more technical and non-obvious aspects of optimising Largest Contentful Paint: Largest Contentful Paint (LCP) is my favourite Core Web Vital. It’s the easiest to optimise, and it’s the only one of the three that works the exact same in the lab as it does in the field (don’t …
From the Polymer team: Tachometer is a tool for running benchmarks in web browsers. It uses repeated sampling and statistics to reliably identify even tiny differences in runtime. To compare two files, run it like so: npx tachometer variant1.html variant2.html Tachometer will open Chrome and load each HTML file, measuring the time between bench.start() and …
Continue reading “Tachometer – Statistically rigorous benchmark runner for the web”
The folks from builder.io set out to create a way to prevent Third-Party Scripts from blocking the main thread. The result is Partytown, which runs Third-Party Scripts Within a Web Worker. Partytown is able to sandbox and isolate third-party scripts within a web worker and allow, or deny, access to main thread APIs. This includes …
Continue reading “Partytown: Run Third-Party Scripts off the Main Thread in a Web Worker”
ct.css – Let’s take a look inside your <head>
Harry Roberts created a utility CSS file ct.css that x-rays your site’s <head>: Your <head> is the single biggest render-blocking part of your page—ensuring it is well-formed is critical. ct.css is a diagnostic CSS snippet that exposes potential performance issues in your page’s <head> tags. <link rel="stylesheet" href="https://csswizardry.com/ct/ct.css" class="ct" /> The CSS basically adds display: …
Continue reading “ct.css – Let’s take a look inside your <head>”
document.body
Very good performance deep dive on why you shouldn’t attach tooltips to document.body, but to a div that’s a direct child of the <body>. Tooltips in our app were taking >80ms. And during this time, the main thread was blocked, you couldn’t interact with anything. The main reason for the slowness of Tooltip was “Recalculate …
ORDER BY RANDOM()
Jake Archibald has published a nice series in which he has been been performance-testing all F1 sites. Not only does he dig into waterfall charts, he also points out a few simple things that could be applied in order to improve overall loading performance. As a bonus he also tested the Google I/O site, which …