JavaScript class helpers See: http://toddmotto.com/creating-jquery-style-functions-in-javascript-hasclass-addclass-removeclass-toggleclass/

js-class-helpers.js

/*
  JavaScript class helpers
  See: http://toddmotto.com/creating-jquery-style-functions-in-javascript-hasclass-addclass-removeclass-toggleclass/
*/

function hasClass(elem, className) {
  return new RegExp(" " + className + " ").test(" " + elem.className + " ");
}

function addClass(elem, className) {
  if (!hasClass(elem, className)) {
    elem.className += " " + className;
  }
}

function removeClass(elem, className) {
  var newClass = " " + elem.className.replace(/[\t\r\n]/g, " ") + " ";
  if (hasClass(elem, className)) {
    while (newClass.indexOf(" " + className + " ") >= 0) {
      newClass = newClass.replace(" " + className + " ", " ");
    }
    elem.className = newClass.replace(/^\s+|\s+$/g, "");
  }
}

function toggleClass(elem, className) {
  var newClass = " " + elem.className.replace(/[\t\r\n]/g, " ") + " ";
  if (hasClass(elem, className)) {
    while (newClass.indexOf(" " + className + " ") >= 0) {
      newClass = newClass.replace(" " + className + " ", " ");
    }
    elem.className = newClass.replace(/^\s+|\s+$/g, "");
  } else {
    elem.className += " " + className;
  }
}