risolto cosi levato l'action dal form e agito con jquery e php
codice:
if(isset($_POST['mod']))
	{echo ("<script type='text/javascript'>
			jQuery(document).ready(function(){
			jQuery('#container-2 > ul > li:first').removeClass('ui-tabs-selected ui-state-active');
			jQuery('#container-2 > ul > li:nth-child(2)').addClass('ui-tabs-selected ui-state-active');
			jQuery('#container-2 > div#tabs-1').addClass('ui-tabs-hide');
			jQuery('#container-2 > div#tabs-2').removeClass('ui-tabs-hide');
			});
	</script>");}