rrweb-cssom

CSSOM

CSSOM.js is a CSS parser written in pure JavaScript. It is also a partial implementation of CSS Object Model.

CSSOM.parse("body {color: black}")
-> {
  cssRules: [
    {
      selectorText: "body",
      style: {
        0: "color",
        color: "black",
        length: 1
      }
    }
  ]
}

Parser demo

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 that exposes a single CSSOM global variable:

➤ git clone https://github.com/NV/CSSOM.git
➤ cd CSSOM
➤ node build.js
build/CSSOM.js is done

To use it with Node.js or any other CommonJS loader:

➤ npm install cssom

Why is this not maintained?

1. I no longer use it in my projects
2. Even though cssom npm package has 26 million weekly downloads (as of April 17, 2023), I haven't made a dollar from my work.

If you want specific issues to be resolved, you can hire me for $100 per hour (which is 1/2 of my normal rate).

Don’t use it if...

You parse CSS to mungle, minify or reformat code like this:

div {
  background: gray;
  background: linear-gradient(to bottom, white 0%, black 100%);
}

This pattern is often used to give browsers that don’t understand linear gradients a fallback solution (e.g. gray color in the example). In CSSOM, background: gray gets overwritten. It does NOT get preserved.

If you do CSS mungling, minification, or image inlining, considere using one of the following:

• postcss
• reworkcss/css
• csso
• mensch

Tests

To run tests locally:

➤ git submodule init
➤ git submodule update

Who uses CSSOM.js