[???]

я нашёл решение:

<div id='aft'>
   <form action='ololo.php' method='POST' enctype='application/x-www-form-urlencoded'>
   </form>
  </div>

<script type='text/javascript'>

obj_aft = document.getElementById('aft');
obj_aft.innerHTML = "<form action='lol.php' method='POST' enctype='application/x-www-form-urlencoded'></form>";

</script>