var currentURL = document.location.href;

// The domain of your web site (no http or www)
var domain = document.location.host.replace(/^www\./gi, '');

function frame(url) {
   with (document) {
      clear();
      write('<frameset rows="50, *">');
      write('<frame src="return.php?back=' + currentURL + '" scrolling="no" noresize="noresize"></frame>');
      write('<frame id="mainFrame" name="main" src="' + url + '"></frame>');
      write('</frameset>');
   }
   return false;
}

function offsiteLink(url) {
   // If the URL is on our domain, it's not an offsite link
   if (url.match(domain)) { return false; }

   // If the URL contains a colon, i.e. "http://someothersite.com", it's offsite
   if (url.match(':')) { return true; }

   // Otherwise, it's a local link (i.e. "page.html")
   return false;
}

with (document) {
   // Step through each link on the page
   for (i=0; i<links.length; i++) {

      // If the link is an offsite link, make it open with a branded frame
      if (offsiteLink(links[i].href)) {
         links[i].target = "_top";
         links[i].onclick = function() { return frame(this.href); };
      }
   }
}