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;