判断checkboxlist 是否选中的js函数

  function CheckRoles(sender, args) {
                var count = ($("#<%=CBLRoles.ClientID %>").find("input[type=checkbox]:checked").length);
                if (count > 0) {
                    args.IsValid = true;
                }
                else {
                    args.IsValid = false;
                }
            }