Question

All
One
Two
three

My requirement is

1. when check All it should check One , Two, Three also.
2. When i uncheck All it should uncheck One , Two, Three also
3. When all check boxes check and uncheck either one , two , three in that case “All” check box should uncheck.
4. check / uncheck should ne toggling

Please help

Answer 1

$(function(){
    $("#all").click(function(){
        $("input:checkbox[name='checkGroup']").attr("checked",$(this).attr("checked"));
    });

    $("input:checkbox[name='checkGroup']:not('#all')").click ( function(){
        var totalCheckboxes = $("input:checkbox[name='checkGroup']:not('#all')").length;
        var checkedCheckboxes = $("input:checkbox[name='checkGroup']:not('#all'):checked").length;

        if ( totalCheckboxes === checkedCheckboxes )
        {
            $("#all").attr("checked" , true );
        }
        else
        {
            $("#all").attr("checked" , false );
        }
    });
});

Demo