title: How to parse an empty JSON object without error in $.post callback
body: <p>If I return nothing to the following post, I get an AJAX parse error:</p>
  
  <pre><code>$.post('user.php', {id: 'job'}, function(data) {
      console.log(data.length);
  },'json');
  </code></pre>
  
  <p>How can I avoid it? I want to avoid the server giving any empty answers (like "0") to limit bandwidth consumption (mobile app).</p>
  
  <p>Thanks</p>