How to grab just one part of a page in jQuery?
<p>I have an form being submitted via AJAX. The response from the server in an entire web page (HTML). I would like to alert only the content within a span tag with the id "message" which exists on that response page. I don't want to alert the entire page. How to do this?</p>

<pre><code>$.ajax({
   url: '/accounts/login/',
   data: $(this).serialize(),
   success: function(output) {
       alert(output)
   }
});
</code></pre>

<p>My code alerts the whole page.</p>
