Last year I did some work on implementing a Selectors API Test Suite, which I’ve just updated to run in IE 8. I’ve uploaded a copy of the suite here: https://johnresig.com/apps/selectortest/ You can get the source here: http://github.com/jeresig/selectortest/tree/master For right now I’m getting the following result: WebKit Nightly 99.3% (16 failing – doesn’t support complex :not() expressions) Fi