title: How do I know that a form input has changed?
body: <p>I have a form generated by <code>&lt;% Ajax.BeginForm() {} %&gt;</code> which contains a lot of inputs and texareas.</p>
  
  <p>When an input value change, I need to know about it and mark the input and the form as "dirty". If the user tries to leave the page without saving, I will ask him or her to confirm abandoning changes.</p>
  
  <p>Any suggestion to how this should be done?</p>