Cette chasse aux interstitiels doit être envisagée dans une approche plus globale d’allégement de son site ou de “désencombrement”.

Au-delà de faciliter la navigation, la réduction de la publicité au strict minimum et la suppression des images ou vidéos inutiles (entre autres) permettent de recentrer l’attention de l’utilisateur.

There are two reasons why people use CSS grid:

• 😎 CSS is awesome! It's a fact, deal with it.
• 🛠️ Grid is a great tool to build complex two-dimensional layouts.

I sometimes have a third reason to use CSS grid: prevent layout shifts.

It is great to see Google create a new Page Experience signal using a brilliant object-oriented approach. I think it is smart, flexible, and scalable. That said, in my opinion, the signal must have teeth in order for it to be taken seriously by site owners, developers, and SEOs. If not, it can fall by the wayside.

Now that you know these metrics, we can use them to understand what’s happening on our sites and to ask better questions.

It would be useful to have insight into the moment when assistive technology is able to interact with and communicate page content, so that we can know when a page is “ready” for all users, and not just some.
[…] It’d be interesting to know which existing metrics are irrelevant to assistive tech
[…] it might be interesting to measure “jank” and stability in the process of arriving at a usable accessibility tree.
[…] how are metrics like First Input Delay translating to the interaction time that someone experiences when using assistive technology?

So you have to be really careful when using this metric, the LCP is not always tracking the element you think

Aussi, nous ne pouvons pas nous empêcher de supposer une volonté de Google de soulager son infrastructure.

Pourquoi vouloir à tout prix rendre un site rapide ? Pas seulement par souci UX ou par amour de son.a prochain.e, mais aussi parce que Google passe du temps à crawler un volume immense de pages.

Performance metrics are surprisingly challenging to get right.

We now track a Page Performance Score based off of four user-centric metrics: (TT)FCP, (TT)FMP, FID, and TBT.

Cumulative Layout Shift (CLS) is a relatively new metric to help you understand the delightfulness of the user experience.

le Synthetic Monitoring présente l’avantage d’offrir une stabilité que les données organiques n’ont pas, donc on en aura toujours besoin. C’est un moyen très efficace de détecter des changements dans la performance qui viennent de nous et non pas de l’environnement. Ces métriques sont toujours utiles sur du très long terme.

This is an experiment to see what amount of delay is too annoying for a user interaction like typing. Here are some presets; make sure to type a lot of characters at once for the full effect.

A great tool to wrap your mind aroung the values of your First Input Delay.

Have you ever been reading an article online when something suddenly changes on the page? Without warning, the text moves, and you've lost your place.

There is a clear pattern of environmental properties having the worst correlation: Effective connection type, device memory, available CPU, page transfer size. This might suggest that users are aware of their device, network quality and page size (small vs big article in Wikipedia's case) and adjust their expectations to those factors.

As a matter of fact, the Time To Interactive does not measure how long it takes for a page to become interactive, it measures how long it takes to be sure, regarding the conditions, that a interactivity can happen in a satisfactory way, for at least 5 seconds.

tl;dr: There are no silver bullets to web performance. Simple static pages benefit from being server-rendered with minimal JavaScript. Libraries can provide great value for complex pages when used with care.

"we have set up a transversal performance monitoring system that provides the basis for actions and a direct assessment of their impact. We no longer address web performance optimization as a problem but rather as a continuous improvement initiative and it perfectly fits with our culture of innovation and excellence."

"This extensive review shows how little we really know about performance perception and how inadequate the metrics currently used as industry standards probably are"

"Accurately measuring layout on the web is hard. There’s no perfect metric to capture style and layout – or indeed, rendering – even though all three can impact the user experience just as much as JavaScript.

However, it’s important to understand how the HTML5 event loop works, and to place performance marks at the appropriate points in the component rendering lifecycle."