I believe this article has a substantial At a high level, all (non-headless) web browsers are composed of 7 parts.In implementations, some of these parts can be combined.I think that in 3-5 years from now we can lose support for IE7 and in 5-7 years it will be perfectly safe to use HTML5 CSS3 without thinking about the older browsers. HTML5 is basically a backwards-compatible superset of HTML4, and CSS3 is a superset of CSS2. But this doesn't mean that HTML4 and CSS2 become obsolete immediately. While everyone would like to think that IE6 is dead there are still plenty of companies that enforce the use of IE6 and aren't looking to migrate any time soon.This means a browser supporting HTML5 will also support HTML4, while the reverse is not true. So HTML4/CSS2 will be more widely supported than the more recent versions, and they will never be obsolete. There is a parallel time when a design with either is accepted. These places will have web applications that work on that version of IE and aren't in a position to switch.The image and list imply that this all happens in a single, gigantic pass. The rendering process is a gradual, asynchronous process.For a better user experience, the rendering engine will attempt to render content ASAP.html5 and css3 are the new things out there but in my opinion they are still experimental, (some new websites remind me of the blink tag).
The vast majority of this article consists of summaries of her content, but I believe I’ve refactored enough parts/added enough content such that my notes are significantly different from her original article — and that it could provide a different experience for readers.
It is an infinite process and I doubt that we will ever reach a point, where the code would be "universal".