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