function externalLinks() {  
	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";  
	}  
}  
window.onload = externalLinks;