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” ) {
if ( anchor.getAttribute(“className”) )
{ anchor.target = anchor.getAttribute(“className”); }
else
{ anchor.target = “_blank”; }
}
}
}

//how to use…
<a href="link1.php" class="newWindow" rel="external"> Link 1 </a>
<a href="link2.php" > Link 2 </a>