how to show alert/confirmation only on uncheck of check box in asp:CheckBoxList by jquery

i have a asp:CheckBoxList and i want to show an warning message only on uncheck of check box in asp:CheckBoxList by jquery,like uncheck of a any item will delete the corresponding record from backend.

   $('.chklist').click(
     function () {
         if ($(this).is(":not(:checked)")) {
             alert(this.id);
         }

     });

but the above code is always giving true even if item is checked or unchecked. as it is taking id for the whole list and not that particular check box. please help, i dont want to implement the things on post back event.