// numbersOnly.js
// Check keystroke input to allow numbers only as input for form fields 
function numbersonly (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);

  // control keys
  if ((key==null) || (key==0) || (key==8) || 
      (key==9) || (key==13) || (key==27))
    return true;

// numbers (w/ optional decimal point)
  else if ((("0123456789").indexOf (keychar) > -1))
    return true;
  else
    return false;
}