อยากทราบวิธีแก้ไข ie 8 เมื่อมีการใช้ ฟังก์ชั่น all checked checkbox

// All Checkbox Function
function allChecked(chkname, flag){
            var objchk = null;
            if (chkname.substring(0,1) == ".") {
              objchk = document.getElementsByClassName(chkname.substring(1));
            } else if (chkname.substring(0,1) == "#") {
              return;
            } else {
              objchk = document.getElementsByName(chkname);
            }
            for (var i=0; i<objchk.length; i++){
			if (objchk[i].type == "checkbox") {
				objchk[i].checked = flag;
			}
		}
}

<table id="tbl_bookinglist">
	<thead>
		<th width="50px"><input type="checkbox" onclick="javascript: allChecked('.chkHotel', this.checked);"></th>
       </thead>
       <tbody>
      <?php
          $round = $_SESSION['Line'];
          for ($i=0;$i<=$round;$i++){ 
        ?>
           <td align="center"  rowspan="<?=$queryCount; ?>"><input type="checkbox" name="chkCartNo[]" class="chkHotel" value="<?=$i; ?>"></td>
      <?php } ?>
       </tbody>