is there a difference from a css point of view between

<div> 
  <form> 
  </form> 
</div>

and..

<form> 
 <div> 
 </div>
</form> 

This can change inheritance, perceived width, and the selectors you use. So, yes, there is a difference.

Aside from the fact to select children one is div > form and the other is form > div no.