if (document.getElementsByClassName == undefined)
{
  document.getElementsByClassName = function (className)
  {
    var hasClassName = new RegExp("(?:^|\\s)" + className + "(?:$|\\s)");
    var allElements = document.getElementsByTagName("*");
    var results = [];
    var element;

    for (var i = 0; (element = allElements[i]) != null; i++)
    {
      var elementClass = element.className;
      if (elementClass && elementClass.indexOf(className) != -1 && hasClassName.test(elementClass))
        results.push(element);
    }

    return results;
  }
}