limit dragging property of a div inside inside another div?

Question

please help me to limit dragging property of a div inside inside another div example http://galtech.org/testing/drag.php i need dragg the red div only inside the blue div pls help me i am using jQuery draggble

<script>
  $(document).ready(function() {
    $("#draggable").draggable();
  });
  </script>

Answer 1

<script>
  $(document).ready(function() {
    $("#draggable").draggable({ containment: 'parent' });
  });
  </script>

suppose blue div is parent

docs here