CSSOM.js is a CSS parser written in pure JavaScript. It also a partial implementation of CSS Object Model.
CSSOM.parse("body {color: black}")
-> {
  cssRules: [
    {
      selectorText: "body",
      style: {
        0: "color",
        color: "black",
        length: 1
      }
    }
  ]
}
Works well in Google Chrome 6+, Safari 5+, Firefox 3.6+, Opera 10.63+. Doesn't work in IE < 9 because of unsupported getters/setters.
To use CSSOM.js in the browser you might want to build a one-file version with Jake:
➤ jake
build/CSSOM.js is done
To use it with Node.js:
npm install cssom