gridview中checkbox的全选与全不选

1.html：

 1   <asp:GridView runat="server" ID="gvAddBySR" AutoGenerateColumns="False" HorizontalAlign="Left"
 2             Width="100%" EmptyDataText="<%$ Resources:GlobalResource,  NoData%>">
 3             <Columns>
 4                 <asp:TemplateField HeaderStyle-Width="7%">
 5                     <HeaderTemplate>
 6                         <input id="CheckAll" type="checkbox" onclick="selectAll(this);" />
 7                     </HeaderTemplate>
 8                     <ItemTemplate>
 9                         <asp:CheckBox runat="server" ID="ck" class="ck" onclick="getCk(this);"/>
10                     </ItemTemplate>
11                 </asp:TemplateField>

2.js

 1  function selectAll(obj) {
 2          var idAll = obj;
 3          Ced = idAll.checked;
 4          UCed = idAll.form.elements;
 5          var c = UCed.length;
 6          for (i = 0; i < UCed.length; i++) {
 7              if (UCed[i].type == "checkbox" && UCed[i] != idAll.id) {
 8                  if (UCed[i].checked != Ced) {
 9                      UCed[i].click();
10                  }
11              }
12          }
13      }