Not really an Element#classList polyfill. IE9 doesn’t have classList, and other browsers have incomplete implementations; hence, this module.

This module is intended for use in the browser via browserify. It can be installed via npm:

$ npm install classlist

And then used like so:

var ClassList = require('classlist')

var element = document.querySelector('.foo'),
    list = ClassList(element)

// Add a class:
list.add('bar')

// Remove another:
list.remove('baz')

// Toggle:
list.toggle('quux')

// Check for existence:
if (list.contains('bar')) {
    alert('Whee')
}

This module mostly tracks the offical API, but returns the context wherever possible; this allows you to do things like:

ClassList(element)
  .add('foo', 'bar')
  .remove('baz')
  .toggle('quux')

Note that using new is optional. Returns an array-like object of the element’s classes. This object has several handy methods; see below.

Adds one or more classes to the element originally used to construct the list. If the class is already present on the element, it is not added again. Returns the context to allow chaining.

Removes one or more classes from the element. Returns the context to allow chaining.

Toggles a class on the element; adds the class if it is not present, and removes it otherwise. When force is true, the class is always added; when false, the class is removed (i.e. .toggle(class, true) is equivalent to .add(class), and .toggle(class, false) is equivalent to .remove(class)). Returns the context to allow chaining.

Returns true if the element has the given class; false otherwise.

ClassList should work in just about every browser, up to and including IE6. If it doesn’t, open an issue.

MIT.