if(stock){

  screen.style.background = "green";
  screen.innerText = "IN STOCK";

  if(!window.stockAlerted){

    window.stockAlerted = true;

    if(navigator.vibrate){
      navigator.vibrate([500,300,500,300,500]);
    }

    alert("POKEMON STOCK AVAILABLE!");

  }

} else {

  window.stockAlerted = false;

  screen.style.background = "red";
  screen.innerText = "OUT OF STOCK";
}