Ajax - responseText working but responseXML null

Question

I am trying my first AJAX and having a problem with my xml receiving function. I alert responseText and I can see the xml returned from my server, but when I try and get responseXML I get null and the error.

Here is the php function that builds my xml

  header('Content-type: application/xml');
    echo("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
    echo("<results>");
    echo("<table><![CDATA[tablereererere]]></table>");
    //echo("<ratedTable>".$_POST['ratedTable']."</ratedTable>\n");
    //echo("<table>".$_POST['table']."</table>\n");
    //echo("<post_id>".$_POST['post_id']."</post_id>\n");
    //echo("<user_id>".$_POST['user_id']."</user_id>\n");
    //echo("<rating>".$_POST['rating']."</rating>\n");
    echo("</results>");

And here is my javascript function which is processing the returned xml

function ajaxReceiver(http_request) {

    //this function continues to run until a result is returned and then it creates the new div
    if(http_request.readyState == 4) {

      response_xml = http_request.responseXML;
      response_text =  http_request.responseText;

      alert(response_text);
      alert(response_xml.getElementsByTagName("table")[0].textContent);
      //document.getElementById('floatingNotification').innerHTML = response_text;
       // alert(http_request.responseXML.getElementsByTagName("table")[0].textContent);
      //ratedTable = responseXML.getElementsByTagName("table").value;
      //alert(ratedTable);
      //message = response.getElementsByTagName('table')[0].textContent;
      //alert(message);
     //alert(message);
//this response contains the xml document that was returned by the php function.You can get any values out of the xml document and 
//use javascript dom to manipulate the contents on the page


    }
}

Answer 1

It may be because, even though you're setting the content-type correctly, you need to have an <xml tag in the top of your response. Also, you aren't closing your last tag properly. This should work:

echo("<?xml version='1.0'?>");
echo("<results>");
echo("<ratedTable>".$_POST['ratedTable']."</ratedTable>");
echo("<table>".$_POST['table']."</table>");
echo("<post_id>".$_POST['post_id']."</post_id>");
echo("<user_id>".$_POST['user_id']."</user_id>");
echo("<rating>".$_POST['rating']."</rating>");
echo("<message>$message</message>");
echo("</results>");

For more info on how to define your XML: http://www.w3.org/TR/REC-xml/#sec-prolog-dtd