function externalLinks()
{
  if (!document.getElementsByTagName)
    return;
  
  var anchors = document.getElementsByTagName("a");
  for (var i = 0; i < anchors.length; i++)
  {
    var anchor = anchors[i];
    //document.write(anchor.getAttribute("rel").indexOf("external"));
    if (anchor.getAttribute("href") && anchor.getAttribute("rel") && anchor.getAttribute("rel").indexOf("external") != -1)
    {
      anchor.onclick = function(x)
      {
        var p = x;
        return function()
        {
          var w = window.open(p);
          if (!w)
          {
            alert("A popup blocker seems to have blocked the window from opening");
          }
          return false;
        }
      }(anchor.getAttribute("href"));
    }
  }
}

window.onload = externalLinks;