asp:Repeater中的CheckBox问题！！（急!!）

 <table width="100%">
                <th scope="col">
                    <asp:CheckBox ID="CheckAll" runat="server" onclick="javascript:SelectAll(this);"
                        title="选择全部" />
                </th>
                <th>
                    姓名
                </th>
                <th>
                    所属类型
                </th>
                <th>
                    发布时间
                </th>
                <th>
                    操作
                </th>
                <asp:Repeater ID="rp_ThemeList" runat="server" OnItemCommand="rp_ThemeList_ItemCommand">
                    <HeaderTemplate>
                    </HeaderTemplate>
                    <ItemTemplate>
                        <tr>
                            <td>
                                 <asp:CheckBox ID="cb_select" runat="server" />
                            </td>
                            <td>
                                <asp:Label ID="lbLomeCode" runat="server" Text='<%#Eval("lome_code") %>' Visible="false"></asp:Label>
                                <%#Eval("lome_name") %>
                            </td>
                            <td>
                                <%#Eval("lome_content") %>
                            </td>
                            <td>
                                <%#Eval("lome_time") %>
                            </td>
                            <td>
                                <a href="EditTeamMember.aspx?lomecode=<%#Eval("lome_code") %>">修改</a>
                            </td>
                            <td>
                                <asp:LinkButton ID="lbDelete" runat="server" Text="删除" CommandName="del" OnClientClick="javascript:return confirm('确定要删除吗？')"></asp:LinkButton>
                            </td>
                        </tr>
                    </ItemTemplate>
                    <FooterTemplate>
                    </FooterTemplate>
                </asp:Repeater>下面是JS代码:
 <script type="text/javascript">
function SelectAll(tempControl)
{
   var theBox=tempControl;
   xState=theBox.checked;
   elem=theBox.form.elements;
   for(i=0;i<elem.length;i++)
   {
     if(elem[i].type=="checkbox" && elem[i].id!=theBox.id)
     {
       if(elem[i].checked!=xState)
       {
         elem[i].click();
       }
     }
   }
}
    </script>
点全选时报错“缺少对象!”