Javascript Close Event.

I have a frame called viewer.

When a herf link if pressed within the frame i would like to check to see if the link they have pressed is a internal link, I.E. is it a link to another part of my site or if another site is going to load within the frame.

I am trying to use the a onClose event to excute javascript to check this. and if it is a extranel link, stop the unload and open up the link in a new window. I have try using PHP to parse the pages and add target="_blank" but because all these pages have been programmed by different people no one uses a standard <a> so a regular expression can't be created so it works all the <a> tags.

so far i have,

just need to know a var that contains the new url that the page is going to change to.

<script>

var cmpto = top.document.location;
cmpto = cmpto.substring(0, cmpto.indexOf("/", 7));
var newloc = ????;
newloc = newloc.substring(0, cmpto.indexof("/", 7));
if (cmpto == newloc) {
// extranel link.
window.open(newloc);
return false;
}else {
// do nothing
return true;
}

Seems like i was going the wrong way about it, running this script at the bottom of each pages does what i need.

<script>

var test = document.location.href;
test = test.substring(0, (test.indexOf('/',8) +1));
for(a = 0; a < document.links.length; a++)
{
if(document.links[a].href.substring(0, test.length) != test) {
document.links[a].target = "_blank";
}
}
</script>