Probá haciendo este reemplazo:
Código PHP:
function attach_menu_option_event(option, evnt, callback)
{
var element = menu_options[option];
if (element.addEventListener)
element.addEventListener(evnt,callback,false);
else if (element.attachEvent){
var fn=function(){
callback.call(element,window.event);
}
element.attachEvent("on"+evnt, fn);
}
}