title: Ajax Error: 200 Response Code
body: <p>I'm using the <a href="http://malsup.com/jquery/form/" rel="nofollow">jQuery Form</a> plugin to handle a form submission with Ajax:</p>
  
  <pre><code>$('.login-form').ajaxForm({
      dataType: 'json',
      success: function(data){
          console.log('Success!');
          console.log(data);
      },
      error: function(data){
          console.log('There was an error:');
          console.log(data);
      }
  })
  </code></pre>
  
  <p>After submission, the ajax returns an error with a status of "200". This is the JSON-formatted response:</p>
  
  <pre><code>{
      "success": false, 
      "heading": "The following errors were encountered", 
      "message": "&lt;ul&gt;&lt;li&gt;The existing username and/or password you submitted are not valid&lt;/li&gt;&lt;/ul&gt;"
  }
  </code></pre>
  
  <p>I ran that through <a href="http://jsonlint.com/" rel="nofollow">jsonlint.com</a>, and it returned as valid.</p>
  
  <p>In Chrome's Network tab, the response is returned as type <code>application/json</code>.</p>
  
  <p>So why is ajax returning "error" rather than "success"?</p>
  
  <p>jQuery 1.9.1</p>