check box Jquery check - uncheck

   <script type="text/javascript">
          $('.checkall [type=checkbox]').click(function () {
              if ($(this).attr('checked')) {
                  var objCheckBox = $('.checkone [type=checkbox]');
                  for (var i = 0; i < objCheckBox.length; i++) {
                      $(objCheckBox[i]).attr('checked', true);

                  }
              }
              else {
                  var objCheckBox = $('.checkone [type=checkbox]');
                  for (var i = 0; i < objCheckBox.length; i++) {
                      $(objCheckBox[i]).attr('checked', false);

                  }
              }
          });
    </script>