CSS Selector matching is used for Style Resolution and SelectorQuerying. We describe CSS Selector JIT in WebKit, optimizing CSS Selector Matching with Just-in-Time compilation techniques. NOTE: http://constellation.github.io/blog/2014/07/14/webkit-css-jit-internals/
![CSS JIT: Optimizing CSS Selector Matching with Just-in-Time Compilation](https://cdn-ak-scissors.b.st-hatena.com/image/square/e126a39fb54f1277f25b20bf03ebad92a5a768b7/height=288;version=1;width=512/https%3A%2F%2Ffiles.speakerdeck.com%2Fpresentations%2F7de34aa0ed5501316f58121af30ec4cc%2Fslide_0.jpg%3F3293372)