function performShorten(a)
{
 var url = "/shorten.php?step=2&url=" + escape(a.form.elements['url'].value); 

 req = new XMLHttpRequest();
 req.open("GET", url, true);
 req.onreadystatechange = handleResponse;
 req.send();

 return false;
}

function handleResponse()
{
  try {
      if (req.readyState == 4) {
         if (req.status == 200) {
            document.getElementById('url01').value =  req.responseText;
            document.getElementById('url01').select();
         } else {
            alert("Error: " + req.statusText + " " + req.responseText);
         }
      }
   } catch(e) {
       alert('handleResponse exception: ' + e.name + '; ' + e.message);
   }
}