Codice:

$(function() {
	$("#draggable").draggable({ revert: 'valid' });
	$("#draggable2").draggable({ revert: 'invalid' });
	$("#droppable").droppable({
		activeClass: 'ui-state-hover',
		hoverClass: 'ui-state-active',
		drop: function(event, ui) {
			$(this).addClass('ui-state-highlight')
				.find('p').html('Rilasciato!');
		}
	});

});