function goBack()
  {
  window.history.back()
  }

var xmlhttp;
// AJAX implementation for van... sites
function loadXMLDoc(url)
{
xmlhttp=null;
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE5, IE6
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
xmlhttp.onreadystatechange=onResponse;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}