Skidanje fajla radi kroz php ne radi kroz ajax

<?php

//echo "test ajax";

header("Content-type: application/vnd.ms-excel");
header("Content-Disposition: attachment; filename=excel.xls");

echo '<table border="1">
<tr>
<td>row 1, cell 1</td>
<td>row 1, cell 2</td>
</tr>
<tr>
<td>row 2, cell 1</td>
<td>row 2, cell 2</td>
</tr>
</table>';


?>
 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" dir="ltr" lang="sr">

<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title></title>

<script type="text/javascript">
  var theDIV; // we will set this to an id that actually exists in the page

  var http_request = false;
  function fromServer()
  {
    if( http_request.readyState==4 )
    {
      if( http_request.status==200 )
      {
// results from call to the server appear here
// in http_request.responseText;
        e = document.getElementById(theDIV);
        e.innerHTML = http_request.responseText;
      }
      else
      {
// uncomment next line if you want to show any error messages
        //alert('error: ' + http_request.responseText);
      }
    }
  }



  function makeRequest(url, parameters)
  {
    http_request = false;
    if( window.XMLHttpRequest )
    {
      // Mozilla, Safari,...
      http_request = new XMLHttpRequest();
      if (http_request.overrideMimeType)
      { http_request.overrideMimeType('text/html');
      }
    }
    else if (window.ActiveXObject)
    { // IE
      try
      { http_request = new ActiveXObject("Msxml2.XMLHTTP");
      }
      catch (e)
      { try
        { http_request = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
      }
    }
    if (!http_request)
    {
// uncomment next line if you want to show any error messages
      //alert('Cannot create XMLHTTP instance');
      return false;
    }
    http_request.onreadystatechange = fromServer;
    http_request.open('GET', url + parameters, true);
    http_request.send(null);
  }

</script>
</head>

<body>

<script type="text/javascript">
var url = "excel.php"
theDIV='div_ajax';
qry = "?";
makeRequest(url,qry);
</script>

<div id="div_ajax"></div>

</body>
</html>