function externalLinks() {
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    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";
            anchor.title = (anchor.title != "") ? anchor.title+" (opens in a new window)" : "opens in a new window";
            anchor.className = (anchor.className != "") ? anchor.className+' external' : 'external';
        }
    }
}
window.onload = externalLinks;