title: why this jquery won't trigger .ajax() request?
body: <p>i have this code</p>
  
  <pre><code>// jquery
  $(document).ready(function() { 
      $('#update_point').live("change", function() {
          var point_val = $('#update_point').val();
          $.ajax({
              url: 'send/user/update_point.php',
              type: 'get',
              data: 'point='+point_val,
              dataType: 'json',
              success: function(data){
                  alert(data);
                  $('#update_point_result').html(data);
              }
          });
          return false;
      });
  });
  </code></pre>
  
  <p>why that code doesn't fired ? but if i'm remove dataType, the code works. why ?</p>
  
  <pre><code>// jquery
  $(document).ready(function() { 
      $('#update_point').live("change", function() {
          var point_val = $('#update_point').val();
          $.ajax({
              url: 'send/user/update_point.php',
              type: 'get',
              data: 'point='+point_val,
              success: function(data){
                  alert(data);
                  $('#update_point_result').html(data);
              }
          });
          return false;
      });
  });
  </code></pre>
  
  <p>any help will be appreaciate it !
  Thanks !</p>
  
  <hr>
  
  <p>edit</p>
  
  <p>update_point.php contains this code.</p>
  
  <pre><code>&lt;?php
  require "../../inc/json.php";
  if($_GET){
      foreach($_GET as $key=&gt;$val){
          $respon[$key] = $val;
      }
  }
  
  // initialitation json object
  
  $json = new Json();
  echo $json-&gt;encode($respon);
  die();
  ?&gt;
  </code></pre>