This leads to a situation for users that’s almost worse than before. Instead of staring at a blank screen, now they get HTML lickety-split—excellent! But if they try to interact with what’s on screen, they’ll find that nothing is working yet. Even worse, once the JavaScript is delivered, and is being parsed, they probably can’t even scroll—their device is too busy interpreting all that JavaScript. Your users suffer.

Comment réduire l’impact des visuels sur les performances de decitre.fr tout en gardant une bonne qualité d’affichage ? WebP, images à haut ratio et LQUIP !

If I would need to implement image lazy-loading on a high-traffic e-commerce site today, I’d very likely go for a JS-based solution. Partly because the native solution only works in Chrome, but also because Chrome’s implementation is too eager and therefore not so effective.

A way of validating data independently of the programming language, a sort of mustache / handlebars, but only in the world of data validation.

For a recent New York Times article, I wanted to see if it was possible to create SVG charts that would work without JS.
[…]
At the New York Times we're using a very similar technique to create JS-less maps tracking the coronavirus outbreak.

Performance improvements are a never-ending journey. The key is to strike the right balance. As noted above, we made significant progress on speed in 2019. But that is not the end of the story. Going forward, we have put a few things in place that will always keep us on the edge when it comes to performance.

• A committee of Speed Champions
• Synthetic monitoring to check budgets before each release
• Adaptive speed budgets
• RUM and interactivity metrics (FID, TTI)

[…] these checks don’t come for free. They can have a significant impact on web performance depending on what browser a user is using, and the location they are browsing from. And if a site uses an EV certificate, it is forcing the most popular browser on the planet (Chrome) to open a revocation check, which will have an impact on performance for those users who visit your site using it. It makes you wonder if the ‘perceived’ advantages of using an EV certificate are really worth it? Personally, I don’t see any advantages, only disadvantages.

A Hugo theme for Reveal.js that makes authoring and customization a breeze. With it, you can turn any properly-formatted Hugo content into a HTML presentation.

Supports de cours JavaScript au format Gitbook, pour étudiants EEMI de 1ère année

Si vous voulez auto-héberger des ressources tierces, voici quelques astuces :

• Auto-hébergez vos bibliothèques JS, polices et CSS critiques. Cela réduira le risque de SPOF ou de dégradation des performances sur le chemin critique.
• Avant de mettre en cache une ressource tierce sur un CDN, assurez-vous qu'elle est versionnée ou que vous pouvez gérer son cycle de vie en vidant manuellement ou même automatiquement le CDN lorsqu'une nouvelle version est publiée.
• Vérifiez votre configuration CDN / proxy / cache pour éviter d'envoyer des cookies de votre domaine et des Clients-Hints à des services tiers.

[…] sans bonnes performances techniques, l’UX de nos produits ne vaut rien. Tu pourras faire les formulaires les mieux conçus de la Terre, mais si tu as des pages qui mettent 10 secondes à se charger, tu peux fermer boutique.

Utilisation d'un reverse proxy pour optimiser la délivrance des JS tiers.

Game-changing impact of GatsbyJS on performance, accessibility and scalability of modern webapps, and how to integrate it with complex business requirements — be it for a brand new project or an existing ReactJS codebase.

A collection of single-purpose online tools for web developers...

Yes it's better to self-host as the performance gains are substantial […] However, Google Fonts is not just a repository of hundreds of free fonts - it is also a clever delivery mechanism […] There is some complexity involved in this (which Google Fonts handles for you) but with WOFF2-only being a realistic option now, and good support of most techniques with inbuilt fallbacks, this is easier than it used to be.

Setting performance budgets doesn’t need to be complex or confusing, you simply need some existing data, some monitoring, and to remember that budgets and targets are two different things. Don’t make life difficult by treating performance budgets as aspirations.

Dark Mode is taking over the inbox—and making sure emails look great in this reading environment is the new big challenge for email marketers.

You can use service workers to significantly reduce the amount of data your users need to request from your server, and as a result you can dramatically improve both the render and load times for your pages.

Free for Commercial and Personal Use. No need to credit, license, or anything.