Class Manipulation

Three functions to help manipulate the class attribute of HTML elements.

hasClass( element, className )

This function checks element to see if it belongs to className and returns a boolean true or false.

addClass( element, className )

Use this to add className to the element.

removeClass( element, className )

Use this to remove className from the element.

function hasClass(el, sName) {
  return !!(el && el.className && (' ' + el.className.replace(/\s+/g, ' ') + ' ').indexOf(' ' + sName + ' ') >= 0);
}

function addClass(el, className) {
  if(!hasClass(el, className))
    el.className += el.className ? ' ' + className : className;
}

function removeClass(el, className) {
  if(hasClass(el, className)) {
    var cn = [], ns = el.className.split(/\s+/), l = ns.length;
    for(var i = 0; i < l; i++)
      if(ns[i] != className)
        cn.push(ns[i]);

    el.className = cn.join(' ');
  }
}