title: jQuery $.ajax DELETE not hitting then()
body: <p>I have some code in a Chrome extension that's successfully using the <code>then()</code> from the xhr response of <code>$.ajax</code>. </p>
  
  <pre><code>  if (request &amp;&amp; request.action === "updateTask") {
      $.ajax({
        type: "PUT",
        url: config.updateTaskApiUrl(storage.apiKey(), request.calendarEntryId),
        data: request.data,
        dataType: "json"
      }).then(function(data) {
        sendResponse(data);
      });
    }
  </code></pre>
  
  <p>however, I now deleting a record and did the same:</p>
  
  <pre><code>  if (request &amp;&amp; request.action === "deleteTask") {
      $.ajax({
        type: "DELETE",
        url: config.updateTaskApiUrl(storage.apiKey(), request.calendarEntryId),
        dataType: "json"
      }).then(function(data) {
        debugger
        sendResponse(data);
      });
    }
  </code></pre>
  
  <p>The <code>debugger</code> line above never gets hit. I've tried <code>done()</code> and putting the <code>success: function() {}</code> as a key in the call too.</p>
  
  <p>The response from the API is returning a 200.</p>
  
  <p><img src="https://i.stack.imgur.com/bFgEy.png" alt="enter image description here"></p>
  
  <p>Any idea why it never hits the <code>then()</code>?</p>