//this function runs when the page is loaded
function init() {
    updateExternalLinks();
}

function updateExternalLinks() {
 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";
 }
}

document.getElementsByClassName = function(classNames, parentElement) {
	var children = parentElement.getElementsByTagName('*');
	var result = Array();
	for(var i=0; i < children.length; i++) {
		if(children[i].className==classNames[0] || children[i].className==classNames[1]) result.push(children[i]);
	}
	return result;
}


window.onload = init;