function getkey(e)
{
  var code;
  if (!e)
    var e = window.event; // nastaveni pro IE
  if (e.keyCode)
    code = e.keyCode; // IE a Mozilla
  else
    if (e.which)
      code = e.which; // NN4
  return code;
}

function enter(e,abutton) {
 key = getkey(e);
 if (key == 13) abutton.focus();
 return true;
}