check a form to see if nothing has changed
<p>In the app I'm working on, the first thing a user needs to do after authenticating is to enter a name in an input form and save it. </p>

<p>If the user tries to leave the form without having entered something and saved it, I would like to be able to detect this behavior and prevent it, possibly with an alert that reminds them they must first save the form (and not give them a choice).</p>

<p>I know how to use jquery .change() to check if the contents of an input box have changed, but I don't know how to check to see if nothing has changed.  </p>
