function chkAll(CheckAll) {
var items = document.getElementsByTagName("input");
for (var i = 0; i < items.length; i++) {
if (items[i].type == "checkbox"){
for (var j = 2; j < 10; j++) {
var id = "ctl00_ContentPlaceHolder1_GridView1_ctl0" + j + "_CheckBox1";
if (items[i].id == id) {
items[i].checked = CheckAll.checked;
}
}
}
}
}

<asp:TemplateField HeaderText="審核">
<HeaderTemplate>
<asp:CheckBox ID="chkAll" onclick='chkAll(this)' runat="server" />
審核
</HeaderTemplate>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" Checked='<%# Eval("isCheck") %>' runat="server" />
</ItemTemplate>
<ItemStyle HorizontalAlign="Center" Width="100px" />
</asp:TemplateField>