function openTargetBlank(e){
	var className = 'externo';
	if (!e) var e = window.event;
	var clickedObj = e.target ? e.target : e.srcElement;
	if(clickedObj.nodeName == 'A' ){
		r = new RegExp("(^| )"+className+"($| )");
		if(r.test(clickedObj.className)){
			window.open(clickedObj.href);
			return false;
		}
	}
}
document.onclick = openTargetBlank;