// Cross-browser implementation of element.addEventListener()

function listen(evnt, elem, func) {
    if (elem.addEventListener)  // W3C DOM
        elem.addEventListener(evnt,func,false);
    else if (elem.attachEvent) { // IE DOM
         var r = elem.attachEvent("on"+evnt, func);
	return r;
    }
    else window.alert('I\'m sorry Dave, I\'m afraid I can\'t do that.');
}

// Use: listen("event name", elem, func);

function listen(event, elem, func) {
    elem = $(elem);
    if (elem.addEventListener)  // W3C DOM
        elem.addEventListener(event,func,false);
    else if (elem.attachEvent) { // IE DOM
         var r = elem.attachEvent("on"+event, func);
	return r;
    }
    else throw 'No es posible añadir evento';
}

// Use:
// listen("event", elem, func);

Snatched this from another post and fixed something I found was not working.

Cross Browser Add Event Listener

JavaScript