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.

"Every bit of JavaScript you add to a site is a potential way in for a hacker. This is doubly true if that JavaScript is hosted by someone else, such as on a public CDN. Subresource Integrity is a browser feature you can use to make sure that the code being used is exactly what you intended."

"For most developers, code caching should “just work”. It works best, like any cache, when things stay unchanged, and works on heuristics which can change between versions. Nevertheless, code caching does have behaviors that can be used, and limitations which can be avoided, and careful analysis using chrome://tracing can help you tweak and optimize the use of caches by your web app."

JavaScript Loading Priorities in Chrome

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.

"In a perfect world, none of our sites would ever block the main thread unnecessarily. We’d all be using web workers to do our non-UI work, and we’d have shouldYield() and a native Scheduling API) built into the browser.

But in our current world, we web developers often have no choice but to run non-UI code on the main thread, which leads to unresponsiveness and jank."

JavaScript is the web’s CO2.

We have recently completed a milestone where we were able to drop jQuery as a dependency of the frontend code for GitHub.com. This marks the end of a gradual, years-long transition of increasingly decoupling from jQuery until we were able to completely remove the library.

Porthole is a small Javascript library that makes it safe and easy to communicate with cross domain iFrames. Porthole relies on hidden iFrames (later referred to a as proxy) to exchange information. The caller sets a url fragment with the message to pass. The proxy by virtue of being served from the same origin as the callee, invokes a callback method with an event object that contains the message read from the url fragment. The message signaling mechanism is based on a resize event.

"IntersectionObserver is a very straight-forward technology. It has a pretty good support in the modern browsers and if you want to implement it for browsers that still (or won’t at all) support it, of course, there is a polyfill for that. But all in all, this is a great technology that allows us to do all sorts of things related to detecting elements in a viewport while helping to achieve a really good performance boost."

"What we would like you to gain from this article is that JS is expensive and should be used sparingly. Make sure you test your website’s performance on low-end devices, under real network conditions. Your site should load fast and be interactive as soon as possible. "

"Managing your service worker cache invalidation is a key step in making your progressive web app a rich robust experience. It ensures that the content your customer sees and interacts with is the freshest content possible. It also guards your app from overstepping the cache quota and potentially causing a complete purge of everything you stored."

"This post will perform an honest audit of the entire “cost” of Boomerang on a page that it is measuring. We will review every aspect of Boomerang’s lifecycle, starting with the loader snippet through sending a beacon, and beyond. At each phase, we will try to quantify any overhead (JavaScript, network, etc) it causes. The goal is to be open and transparent about the work Boomerang has to do when measuring the user’s experience."

Techniques for faster rendering

What to expect in 2018?

Mutating Web content using DOM Ranges