A simple collection of functions to add classes, remove classes, and toggle classes on elements.

Class Manipulation

var Class = (function() {

  'use strict';

	function addClass(el, className) {
		/**
		* Adds a string to the class name.
		*
		* @param {Node} el Any element
		* @param {String} className The new class name to add
		* @return {String} Returns the new className
		*/
		
		if (el.nodeType === 1 && typeof className === 'string') {
			el.className += ' ' + className;
			el.className = el.className.replace(/\s{2,}/g, ' ');
			return el.className;
		}
	}

	function removeClass(el, className) {
		/**
		* Removes a string from the node's class list.
		*
		* @param {Node} el Any element
		* @param {String} className The class name to remove
		* @return {String} Returns the new className
		*/
		
		if (el.nodeType === 1 && typeof className === 'string') {
			return el.className = el.className.replace(
		        new RegExp('(^|\\s+)' + className + '(\\s+|$)', 'g'),
		        '$1'
			);
		}
	}

	function toggleClass(el, classNames) {
		/**
		* Toggles classes on node.
		*
		* @param {Node} el Any element
		* @param {Array} classNames Array of two strings to toggle between
		* @return {String} Returns the new className
		*/

		if (el.nodeType === 1 &&
			classNames.length === 2 &&
			typeof classNames[0] === 'string' &&
			typeof classNames[1] === 'string') {
			
			removeClass(el, classNames[0]);
			removeClass(el, classNames[1]);
			addClass(el, classNames[1]);
			return el.className;
		}
	}

	return {
		add: addClass,
		remove: removeClass,
		toggle: toggleClass
	};
})();