title: jQuery - ui.keyCode.TAB
body: <p>I am doing a check on a keypress event (event.keyCode === $.ui.keyCode.TAB), and I am consistently getting - </p>
  
  <pre><code>$.ui.keyCode.TAB is null or not an object.
  </code></pre>
  
  <p>What could be causing that? am I missing a .js file somewhere?</p>