window.onload = InitializePage

function InitializePage() {
    SetAnchors();
}

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