title: Forms change style of input "text" to alert user if they click on the box and leave it empty
body: <p>For this form, stroke will be red to alert user <b>if they click on the box and leave it empty</b>.<br/>
  **<br/>
  I want to trigger this <b>without submitting the form</b>.
  Can i do this with only HTML5 and CSS. How?
  If i need JavaScript what is the code?</p>
  
  <p><a href="http://i.imgur.com/uzAuKzM.jpg" rel="nofollow">http://i.imgur.com/uzAuKzM.jpg</a></p>