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