ASP.NET / javascript获取并设置服务器控件checkbox的checked属性

 <script type ="text/javascript" >
       function CheckAllC(oCheckbox)
     {
            var GridView1 = document.getElementById("<%=gvMessage.ClientID %>");
           for(var i = 1;i < GridView1.rows.length; i++)
           {
                GridView1.rows[i].cells[0].getElementsById("cbSingle").Checked =oCheckbox.checked;
           }
      }
 </script>