title: How to get 'getJSON' response header
body: <p>I need to access the size of response message I am getting from another machine (cross-domain request) using $.getJSON, although I can see the request and response in chrome console, it does not work. Here is my request code:</p>
  
  <pre><code>xhr=$.getJSON('http://192.168.1.102/server/server.php?callback=?',   
  {data:array}, function(res){
  alert(xhr.getAllResponseHeader());
  }, 
  type='json'); 
  </code></pre>
  
  <p>when running I get "Uncaught TypeError: Object # has no method 'getAllResponseHeader' " error. When I use</p>
  
  <pre><code>alert(xhr.getResponseHeader("Content-Length"));
  </code></pre>
  
  <p>I get "null". </p>
  
  <p>Please consider that I am using cross-domain get.</p>