I personally think the friendly rivalry between the open-source Webkit engine (which powers Safari, among other things) and Mozilla (the Gecko engine, actually) is one of the best things to happen to browser development in years. The constant one-upsmanship can only lead to better browsers. Well, Internet Explorer will constantly be the limiting factor, but we can dream, can’t we?
The latest thing to hit browser source repos is javascript engine improvement based on something called “trace trees”: essentially, javascript gets translated into native bytecode. The Webkit engine made the announcement a few months ago, with code codenamed “Squirrelfish,” promising massive improvements. That article’s also got a pretty good writeup.
Open Source being what it is, it was only a matter of time before Mozilla announced their own version of a trace-tree-based javascript engine. John Resig has a good writeup, as done Brendan Eich.
