GridView全选和反选用JQuery实现(转)

<asp:GridView ID="grid" runat="server" AutoGenerateColumns="false" GridLines="Horizontal"
            OnPreRender="grid_PreRender">
            <Columns>
                <asp:TemplateField>
                    <HeaderTemplate>
                        <input type="checkbox" id="chkAll" />
                    </HeaderTemplate>
                    <ItemTemplate>
                        <input type="checkbox" id="chkItem" code='<%# Eval("Code") %>' />
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="Code" HeaderText="Code" HtmlEncode="true" />
                <asp:BoundField DataField="Name" HeaderText="Name" HtmlEncode="true" />
                <asp:BoundField DataField="Age" HeaderText="Age" HtmlEncode="true" />
                <asp:BoundField DataField="Address" HeaderText="Address" HtmlEncode="true" />
            </Columns>
        </asp:GridView>

//全选/反选
    $("#chkAll").click(function () {
        $('#<%=grid.ClientID %> > tbody > tr > td > input:checkbox').attr("checked", this.checked);
    });

    //若所有tbody中的项都选中了,自动将表头中的chkAll选中.
    $("#<%=grid.ClientID %> > tbody > tr > td > input:checkbox").click(function () {
        //获取所有选中的checkbox元素
        var expression1 = $("#<%=grid.ClientID %> > tbody > tr > td > input:checkbox:checked");
        //获取所有checkbox元素
        var expression2 = $("#<%=grid.ClientID %> > tbody > tr > td > input:checkbox");
        var hasChecked = $(expression1).length == $(expression2).length;
        $("#chkAll").attr("checked", hasChecked);
    });

    //获取表格中选中的值
    $("#btnGetByGridCheckedElement").click(function () {
        var selectedCodes = new Array();
        var checkedItems = $("#<%=grid.ClientID %> > tbody > tr > td > input:checkbox:checked[@name$='chkItem']");
        $.each(checkedItems, function () {
            selectedCodes.push(this.code);
        });
        if (0 == selectedCodes.length) {
            alert("没有选中任何项..");
            return;
        }
        alert(selectedCodes.join(","));
    });