addLoadEvent

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

addLoadEvent

原文：http://www.cnblogs.com/Rannie/p/5018295.html