​

    $(document).ready(function () {

      var allCheckBoxSelector = $('#chkAll');

​

      var checkBoxSelector = $('input:checkbox:not(#chkAll)');

​

    function ToggleCheckUncheckAllOptionAsNeeded()

    {   

        var totalCheckboxes = $(checkBoxSelector),       

            checkedCheckboxes = totalCheckboxes.filter(":checked"),

            noCheckboxesAreChecked = (checkedCheckboxes.length === 0),

            allCheckboxesAreChecked = (totalCheckboxes.length === checkedCheckboxes.length);

       //console.log(allCheckboxesAreChecked);

​

      $(allCheckBoxSelector).prop('checked', allCheckboxesAreChecked);

    }

​

      $(allCheckBoxSelector).on('click', function ()

      {

          $(checkBoxSelector).prop('checked', $(this).is(':checked'));

​

          ToggleCheckUncheckAllOptionAsNeeded();

      });

​

      $(checkBoxSelector).on('click', function()

      {

        ToggleCheckUncheckAllOptionAsNeeded();

      });

    });