title: Can't receive json data from PHP in Chrome and Opera
body: <p>I have problems with JSON on Chrome and Opera for several days, I managed to fix some errors but now I'm stuck and can't find a way out. I create some array in PHP, encode it in JSON and send it to javascript file where I process it further. In Firefox everything is ok, but in Chrome and Opera <code>$.post()</code> function is never called. I assume it stop working when javascript needs to receive JSON data. Your help is so much needed.</p>
  
  <p>This is my javascript function:</p>
  
  <pre><code>var updateGroup = function(id){
  
      $("#unshareTable").html("");
      passID = id;
      $.post("getData.php", {'id' : id}, function(obj){
          globalColor = obj.color;
          $("#updateGroupTitle").val(obj.title);
          $("#updateColorpickerHolder").css("background-color", obj.color);
          $("#updateColorHex").html(obj.color);
          var color2 = lighterColor(obj.color, .4); 
          $("#updateColorHex2").html(color2);
          $("#updateGroupDescription").html(obj.description);
          $("#unshareTable").append("&lt;tr id='firstRowUnshare'&gt;&lt;td&gt;Username&lt;/td&gt;&lt;td&gt;Option&lt;/td&gt;&lt;/tr&gt;");
          $.post("getUnshareData.php", {'title' : obj.title}, function(obj1){
              var length = obj1.length;
  
              for(var i = 0; i &lt; length; i++){
                  $("#unshareTable").append("&lt;tr&gt;&lt;td class='unshareUsername'&gt;"+obj1[i].username+"&lt;/td&gt;&lt;td&gt;&lt;label class='unshareOneButton'&gt;Unshare&lt;/label&gt;&lt;/td&gt;&lt;/tr&gt;");
              }
          }, "json");
      }, "json");
      $(".updateGroupDiv").fadeIn(300);
  }
  </code></pre>
  
  <p>and simple PHP script</p>
  
  <pre><code>&lt;?php 
      $id = clean($_POST['id']);
  
      $query = $mysqli-&gt;query("select * from groups where id_group = '$id'");
      $data = $query-&gt;fetch_assoc();
      echo json_encode($data);
  
  ?&gt;
  </code></pre>
  
  <p>Also in Chrome I get these error:</p>
  
  <pre><code>Uncaught TypeError: Cannot call method 'getURL' of undefined
  
  Uncaught TypeError: Cannot read property 'onRequest' of undefined
  </code></pre>