original: https://gist.github.com/eirikbacker/2864711 addeventListener

addEventListener-polyfill.js

//addEventListener polyfill 1.0 / Eirik Backer / MIT Licence : Improved by brunoais
(function(win, doc){
	if(win.addEventListener)return;		//No need to polyfill

	function docHijack(p){var old = doc[p];doc[p] = function(v){return addListen(old(v))}}
	function addEvent(on, fn, self){
		// There are events IE does not support. This will translate those to the best option available
		switch(on){
			case 'DOMContentLoaded': on = 'load';
			break;
		}
		return (self = this).attachEvent('on' + on, function(e){
			e = e || win.event;
			e.preventDefault  = e.preventDefault  || function(){e.returnValue = false}
			e.stopPropagation = e.stopPropagation || function(){e.cancelBubble = true}
			e.target = e.srcElement;
			e.relatedTarget = e.toElement;
			fn.call(self, e);
		});
	}
	function addListen(obj, i){
		if(i = obj.length)while(i--)obj[i].addEventListener = addEvent;
		else obj.addEventListener = addEvent;
		return obj;
	}

	addListen([doc, win]);
	if('Element' in win)win.Element.prototype.addEventListener = addEvent;			//IE8
	else{		//IE < 8
		doc.attachEvent('onreadystatechange', function(){addListen(doc.all)});		//Make sure we also init at domReady
		docHijack('getElementsByTagName');
		docHijack('getElementById');
		docHijack('createElement');
		addListen(doc.all);	
	}
})(window, document);