/**
* cross-browser event handling for IE5+, NS6+ and Mozilla/Gecko
* by Scott Andrew
*/
function addEvent(elm, evType, fn, useCapture){

	if(elm.addEventListener){
		elm.addEventListener(evType, fn, useCapture);
		return true;
	}else if(elm.attachEvent){
		var r = elm.attachEvent('on' + evType, fn);
		return r;
	}else{
		elm['on' + evType] = fn;
	}
}