XPath Overnight

A fascinating thing has happened in the world of JavaScript DOM traversal: Over the course of a couple months in 2007 three of the major JavaScript libraries (Prototype, Dojo, and Mootools) all switched their CSS selector engines to using the browser's native XPath functionality, rather than doing traditional DOM traversal. What's interesting about this is that the burden of functionality and performance has, literally, flipped overnight on to the browser's XPath engine, from its pure DOM implementation.