var IE = (navigator.appName.indexOf('Microsoft')!=-1);
var IE6 = ((IE) && (navigator.appVersion.indexOf('6.')!=-1));

// http://www.onlinetools.org/articles/unobtrusivejavascript/chapter4.html
function addEvent(obj, evType, fn){
 if (IE) { eval('obj.on'+evType+'='+fn); return true;}
 if (obj.addEventListener) { obj.addEventListener(evType, fn, false); return true; } 
 else if (obj.attachEvent) { var r = obj.attachEvent("on"+evType, fn); return r; } 
 else return false;
}