通过脚本实现DataGrid控件中CheckBox全选

通过脚本实现DataGrid控件中CheckBox全选
脚本部分如下：

<script>
            function selectAll(oCheckBox)
>

<asp:datagrid id="dgTaskList" runat="server" Width="100%" DataKeyField="PDID" AllowCustomPaging="False"
                            AutoGenerateColumns="False">
                            <HeaderStyle CssClass="headerStyle" ForeColor="white" HorizontalAlign="Center" />
                            <ItemStyle BackColor="white" />
                            <AlternatingItemStyle BackColor="#EEEEEE" />
                            <Columns>
                                <asp:TemplateColumn HeaderText="选择" ItemStyle-HorizontalAlign="center" ItemStyle-Width="60px">
                                    <HeaderTemplate>
                                        <input id="checkBox1" type="checkbox" onclick="selectAll(this)" runat="server"><label>全选</label>
                                    </HeaderTemplate>
                                    <ItemTemplate>
                                        <asp:CheckBox Runat="server" ID="ck"></asp:CheckBox>
                                    </ItemTemplate>
                                </asp:TemplateColumn>
                                <asp:BoundColumn DataField="ProductID" HeaderText="ID码" ReadOnly="True" ItemStyle-Width="100px"></asp:BoundColumn>
                                <asp:BoundColumn DataField="CHName" HeaderText="中文名称" ReadOnly="true" ItemStyle-Width="80px"></asp:BoundColumn>
                                <asp:BoundColumn DataField="ENName" HeaderText="英文名称" ReadOnly="True" ItemStyle-Width="120px"></asp:BoundColumn>
                                <asp:TemplateColumn HeaderText="描述信息" ItemStyle-Width="280" ItemStyle-HorizontalAlign="Left">
                                    <ItemTemplate>
>

后台代码部分省略......