Jquery working with literal value, but not my PHP returned JSON data from $.post

I'm using jQuery's $.post to get values from a query and (trying to) populate a form with those values. The populate plugin needs a JSON object. To test my success callback, I alert and display the data - which looks like valid JSON to me, but the plugin doesn't load the form field. However, if I substitute a literal value e.g. {"cust_id": "65"}, it works. What's the issue? Thanks.

.....here's the cli开发者_运维技巧ent side:

 <script type="text/javascript">

    $(".button").click(function () {        

      var suite = $("input#suite_no").val();

      $.post("get_custrec.php",
        { suite_no: suite },
        function(data){
           data = data.substring(1, data.length-1);
           $('#output').html(data);
           alert("Data: " + data);
           $('#custForm').populate(data);
         }
       );
       return false;
    });
    </script>

.......my server (php) code:

  $result = mysql_query($sql);

  $arr = array();
  while($obj = mysql_fetch_object($result)) {
    $arr[] = $obj;
  }
  echo json_encode($arr); 

$.post("get_custrec.php",
    { suite_no: suite },
    function(data){
       data = data.substring(1, data.length-1);
       $('#output').html(data);
       alert("Data: " + data);
       $('#custForm').populate(data);
     }, 'json' //just need to add this ;)
   );

If you don't specify the dataType that will be returned, jQuery tries to guess it by looking at the response's MIME type (e.g. the HTTP Content-Type header). Since it doesn't look like you're setting the header, you need to:

• set the correct HTTP header: header("Content-Type: application/json"); and/or

• tell jQuery what the dataType is, with one more argument to $.post():

  $.post('get_custrec.php', {...}, function (data) {...}, 'json')

Either one will suffice; using both will not hurt.