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

function externalLinks() { 
 if (!document.getElementsByTagName) return; 
 var anchors = document.getElementsByTagName("a"); 
 for (var i=0; i<anchors.length; i++) { 
   var anchor = anchors[i]; 
   if (anchor.getAttribute("href") && 
       anchor.getAttribute("rel") == "external") 
     anchor.target = "_blank"; 
 } 
} 
//window.onload = externalLinks;
AddLoadEvent(externalLinks);