Here is the cross browser code in adding multiple events in an element inside a document.
var addEvent = function ( el , ev , func ) {
var evnt = el['on'+ev];
el['on'+ev]= function () {
if ( typeof evnt == "function" ) { evnt ();}
func ();
}
};
//example:
function ex () {
alert(2);
}
addEvent (window , "load" , (function(){alert(1);}));
addEvent ( window, "load" , ex );