document.getElementsByClassName = function(classname, fromNode) {
    var a = [];
    var re = new RegExp('(^| )'+classname+'( |$)');
    var els = ((!fromNode)?document:fromNode).getElementsByTagName("*");
    for (var i=0, j=els.length; i<j; i++)
        if (re.test(els[i].className)) a.push(els[i]);
    return a;
};

/**
 * @author: James Bon
 * Fix window.addEventListener method different to IE (attachEvent)
 */
if (!document.addEventListener) {
	document.addEventListener = function(whichEvent, handler, direct) {
		if (document.attachEvent) {
			document.attachEvent('on' + whichEvent, handler);	
		}
	};
}