XMLHttpRequest on Safari

Hello,

I have the following JavaScript code:

Code:

---


<script language="javascript">
var xmlhttp;
        if (window.XMLHttpRequest) {
                // code for IE7+, Firefox, Chrome, Opera, Safari
                xmlhttp=new XMLHttpRequest();
        } else if (window.ActiveXObject) {
                // code for IE6, IE5
                xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
        } else {
                alert("Your browser does not support XMLHTTP!");
        }

        xmlhttp.open( "GET", "http://www.w3schools.com/xml/plant_catalog.xml", true ); 
    xmlhttp.send(null);

      xmlhttp.onreadystatechange = function ()
          {
                alert( xmlhttp.responsetext );
        document.write(xmlhttp.responsetext);
          }
</script>

---

In Safari it comes up saying: undefined.

does anyone know why its doing this?

I am running Safari 5.1.2.

Or does anyone know another way of viewing an XML/or, another page client-side, without using php or asp (server-side).