Why database variables do not show up from AJAX response

[Izzmo]

I could not find ANYTHING on the internet regarding this, and it's starting to really annoy me.

It does not work any any browser.

What happens is this: I have an XMLHttp object setup, it requests a PHP page, the PHP works through everything and then populates an HTML table with database row values.

It returns the table without the database row values.

What the hell?

Any help would be appreciated.

// XMLHttp Ajax Object
  var xmlhttp;
  function loadXMLDoc(url)
  {
   xmlhttp = null;
   var returntxt = "";
   if (window.XMLHttpRequest)
    xmlhttp = new XMLHttpRequest();
   else if (window.ActiveXObject)
    xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
   if (xmlhttp != null)
   {
    xmlhttp.onreadystatechange = function()
    {
     if (xmlhttp.readyState == 4)
     {
      if (xmlhttp.status == 200)
      {
       alert(xmlhttp.responseText);
       returntxt = json_parse(xmlhttp.responseText);
      }
      else
       alert("Problem retrieving XML data");
     }
    };
    xmlhttp.open("GET", url, false);
    xmlhttp.send(null);
    return returntxt;
   }
   else
    alert("Your browser does not support XMLHTTP.");
  }

PHP Code:

       $db = new DB;
       $results = $db->getVehicleMeasures($_GET["year"], $_GET["make"], $_GET["model"], $_GET["trim"]);
       $row = mysql_fetch_row($results);
       echo json_encode("<p>Total Square Feet: ".(String)$row[0]."</p>
        <table style=\"width: 100%;\">
         <tr>
          <td><div style=\"background-color: #000000; line-height: 2px;\">&nbsp;</div></td>
          <td style=\"font-weight: bold;text-size: 14pt; width: 20px;\">OR</td>
          <td><div style=\"background-color: #000000; line-height: 2px;\">&nbsp;</div></td>
         </tr>
        </table>
        <p>Individual Square Feet per Section:
        <table style=\"width: 100%;\">
         <tr>
          <td>Front Bumper: ".(String)$row[1]."</td>
          <td>Rear Bumper: ".(String)$row[2]."</td>
         </tr>
         <tr>
          <td>Hood: ".(String)$row[3]."</td>
          <td>Roof: ".(String)$row[4]."</td>
         </tr>
         <tr>
          <td>Rear Side: ".(String)$row[5]."</td>
          <td>Front Side: ".(String)$row[6]."</td>
         </tr>
         <tr>
          <td>Sides: ".(String)$row[7]."</td>
          <td>Mirrors: ".(String)$row[10]."</td>
         </tr>
         <tr>
          <td>Back Window: ".(String)$row[8]."</td>
          <td>Side Windows: ".(String)$row[9]."</td>
         </tr>
        </table></p>");
       $db = null;