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;