title: jQuery AJAX response always returns nothing
body: <p>The following code returns a blank response no matter whether or not the Function exists, or even the Web Service file entirely:</p>
  
  <pre><code>$.ajax({
      url: "/ws.asmx/HelloWorld"
      , type: "POST"
      , contentType: 'application/json; charset=utf-8'
      , data: '{ FileName: "' + filename + '" }'
      , dataType: 'json'
      , success: function (data) {
  
      }
  });
  </code></pre>
  
  <p>Why is this?</p>
  
  <p>Also, might be worth noting, <code>$.load()</code> works fine!</p>