function keyRestrict(e, validchars)
 {
  var key='', keychar='';
  key = getKeyCode(e);
  if (key == null) return true;
  keychar = String.fromCharCode(key);
  keychar = keychar.toLowerCase();
  validchars = validchars.toLowerCase();
  if (validchars.indexOf(keychar) != -1)
   return true;
  if ( key==null || key==0 || key==8 || key==9 || key==13 || key==27 )
   return true;
  //alert("Plese enter a valid character.");
  return false;
 }

 function getKeyCode(e)
 {
  if (window.event)
   return window.event.keyCode;
  else if (e)
   return e.which;
  else
   return null;
 }