Removing Selected Item from Dropdownlist inside Gridview Using Javascript.

<script language="Javascript">
function checkDuplicate(objID)
{
//put total row count in hidden field
iRowCnt = new Number(document.getElementById("hdnRowCount").value);
var iCheckedIndex; 
var dropDownVal;
   
//get selectedvalue in variable
var szSelVal = objID.value;

for(i = 1; i <= iRowCnt; i++)
{
  dropDownVal = document.getElementById("gvPack_ctl0" + (i + 1) + "_ddl1").value;

  //compare values
  if (szSelVal == dropDownVal)
  {
    alert("Alreay selected");
    return false;
  }
}
</script>