How Browsers Work: Behind the Scenes of Modern Web Browsers

This is probably my biggest problem with most of the ideology behind HTML 5. You learn from past mistakes and HTML has no way to teach you anything because there is no error-correction-test feedback cycle.

How do you learn proper HTML? You write something, you load it in a browser, does it show properly? It was right. Does it show in a funny way? There must be something wrong. What? Who knows. Nobody knows because you cannot, by definition create _wrong_ HTML 5. It is just that you did not write what you think you wrote.

There are validators you can use to validate your page. But most of the times they will tell you that your page is wrong while it actually looks perfectly as you wish in the browser. The browser is not complaining and the page looks good... these validators must be too picky, a waste of time.

The problem that killed XHTML was the draconian error handling in most browser. Only Opera had a good way to handle XHTML errors: a banner that told you that the page had an error and which error. Under that banner the page, rendered as best as possible. That was a good way to learn (and to tell people that the person who wrote the site is not a pro).

"It is important to note that Chrome, unlike most browsers, holds multiple instances of the rendering engine - one for each tab. Each tab is a separate process."

This is not true and has never been true to my knowledge without restricting the statement. Chrome will open links opened in a new tab/window which point to the same domain in the same content process and it will start mixing different domains in the same content processes once a certain threshold is reached (whether this is a hard-coded upper limit on how many content processes may exist simultaneously or if this is calculated dynamically I do not know).

Personally, I'm happy for the repost - I was looking for this, but couldn't find it, just yesterday.

"Firefox blocks all scripts when there is a style sheet that is still being loaded and parsed. Webkit blocks scripts only when they try to access certain style properties that may be affected by unloaded style sheets."

"WebCore simply throws a global switch when any sibling selector is encountered and disables style sharing [optimization] for the entire document when they are present. This includes the + selector and selectors like :first-child and :last-child."

"After parsing the style sheet, the rules are added to one of several hash maps, according to the selector. There are maps by id, by class name, by tag name and a general map for anything that doesn't fit into those categories." Every element then looks in these maps to find rules which might apply to it.

From a high-level view, I hope we see super-intense competition of tablet browsers soon. Because looking at -webkit-on-iPad, I feel IE6 has just been re-invented.