So Firefox 2 is out, and it looks much like its predecessor. The upgrade was painless, nothing broke. So what, exactly, changed? Well one thing is that it has support for JavaScript 1.7, which (among other things) includes support for array comprehensions via iterators, generators, and other Pythonic things.

What caught my eye was that it supports map natively. For anyone using Prototype and getting annoyed with its performance, this could be a big thing. In a few simple tests I found that the exact same loop code runs 2-3 times faster with the native map as compared to Prototype’s implementation. If we could somehow harness that power…