function number(e) {
  var key;
  var keychar;
  if (window.event)
   key = window.event.keyCode;
  else if (e)
   key = e.which;
  else
   return true;
  keychar = String.fromCharCode(key);
  keychar = keychar.toLowerCase();
  // control keys
  if ((key==null) || (key==0) || (key==8) || 
   (key==9) || (key==13) || (key==27) )
   return true;
  // alphas and numbers
  else if ((("0123456789").indexOf(keychar) > -1))
   return true;
  else
   return false;
}