javascript中CheckBox全选终极方案

<asp:Repeater ID="rptGroup" runat="server"> 
  <HeaderTemplate> 
    <table width="100%" cellspacing="1" >
      <tr> 
        <td width="3%" align="center" >
         <input type="checkbox" id="chkAll" name="chkAll" value="checkbox" 
         onclick="checkAll  ('chkAll',this);" />             
        </td> 
      </tr> 
  </HeaderTemplate> 
  <ItemTemplate> 
    <tr> 
    <td align="center" >
     <input type="checkbox" name="chkSelect" value='<%# Eval("ID") %>' 
     onclick="checkAll('chkAll',this);"/>
    </td> 
    </tr> 
  </ItemTemplate> 
  <FooterTemplate> 
    </table> 
  </FooterTemplate> 
 </asp:Repeater> 

function checkAll(chkAllID, thisObj) {
  var chkAll = document.getElementById(chkAllID);
  var chks = document.getElementsByTagName("input");
  var chkNo = 0;
  var selectNo = 0;
  for (var i = 0; i < chks.length; i++) {
    if (chks[i].type == "checkbox") {
      //全选触发事件  
      if (chkAll == thisObj) {
        chks[i].checked = thisObj.checked;
      }
      //非全选触发 
      else {
        if (chks[i].checked && chks[i].id != chkAllID)
          selectNo++;
      }
      if (chks[i].id != chkAllID) {
        chkNo++;
      }
    }
  }
  if (chkAll != thisObj) {
    chkAll.checked = chkNo == selectNo;
  }
} 

function checkSelectNo(chkAllID) {
  var chks = document.getElementsByTagName("input");
  var selectNo = 0;
  for (var i = 0; i < chks.length; i++) {
    if (chks[i].type == "checkbox") {
      if (chks[i].id != chkAllID && chks[i].checked) {
        selectNo++;
      }
    }
  }
  return selectNo;
}