function attachEventListener(target, eventType, functionRef, capture) {
    if (typeof target.addEventListener != "undefined") {
        target.addEventListener(eventType, functionRef, capture);
    } else if (typeof target.attachEvent != "undefined") {
        target.attachEvent("on" + eventType, functionRef);
    } else {
        return false;
    }
    return true;
}

function getElementsByClass(searchClass, node, tag) {
	var classElements = new Array();
	if (node == null) node = document;
	if (tag == null) tag = "*";
	var els = node.getElementsByTagName(tag);
	var elsLen = els.length;
	var pattern = new RegExp("(^|\\s)" + searchClass + "(\\s|$)");
	for (i = 0, j = 0; i < elsLen; i++) {
		if (pattern.test(els[i].className)) {
			classElements[j] = els[i];
			j++;
		}
	}
	return classElements;
}

function target_blank() {
	if (!document.getElementsByTagName) return;
	var i;
	var enlaces = document.getElementsByTagName("a");
	var cuantos = enlaces.length;
	for (i = 0; i < cuantos; i++) {
		if (enlaces[i].getAttribute("href") && enlaces[i].getAttribute("rel") == "external") enlaces[i].target = "_blank";
	}
}
attachEventListener(window, "load", target_blank, false);