function addLoadEvent(func) {
 var oldonload = window.onload; 
if (typeof window.onload != 'function') { 
window.onload = func; 
} 
else { 
window.onload = function() { 
if (oldonload) { oldonload(); } func(); } } }

function isDefined(variable) { return (typeof(window[variable]) == "undefined") ? false : true; }