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"; 
        }
    } 
} 
var oldOnLoad = window.onload;
if (typeof window.onload != 'function') {
    window.onload = function() {
       externalLinks();
    };
}
else {
    window.onload = function() {
        oldOnLoad();
        externalLinks();
    };
}