function addFriend(selectlistID, textBoxID) {

  var txtFriendEmail = document.getElementById(textBoxID);
  var sltFriendList = document.getElementById(selectlistID);

  if (txtFriendEmail.value.length > 0) 
  {
    sltFriendList.Add(txtFriendEmail.value, txtFriendEmail.value);
    txtFriendEmail.value = "";
  }
}

function removeFriend(selectlistID) {
  var sltFriendList = document.getElementById(selectlistID);
    
  for (i= 0; i < sltFriendList.length; i++) {
    if (sltFriendList.options[i].selected) {
      sltFriendList.Remove(i);
      i--;
    }
  }
}