Jquery Compare original state of checkbox with change state

what i want to do is that, i want to hold the value of the checkbox(original state) and then on checkbox state change check if the state is not original state then show a textarea.

what i have done till now

<script>
    var status = $('#status').val();
    $(document).ready(function() {
        status = $('#status').is(":checked");
        $('#status').on('click', function() {
           if( $('#status').is(":checked")!=status){
               $('#mandatory').html('*');
           }else{
               alert("else");
               $('#mandatory').html('');
           }
        });
    });
</script>

problem i am facing is that it is not comparing two values.