jQuerycheckbox全选和全部取消

//chkAll选中，全部chk选中  ,chkAll取消选中,全部chk取消选中 

$("#chkAll").click(function () {

                $(".chk").PRop("checked", $(this).prop("checked"))

           })

   //chk全部选中时，“全选选中”

            $(".chk").click(function () {

                var flag = true;

                var chk = $(".chk")

                for (var i = 0; i < chk.length; i++) {

                    if ($(chk[i]).is(':checked') == false) {

                        flag = false

                        break

                    }

                }

                if (flag == true)

                    $("#chkAll").prop("checked", "checked")

                else

                    $("#chkAll").removeProp("checked")

            })