我如何遍历这个，直到我迷失了方向

我想我还差得远，但是我正在尝试创建一个场景，单击ID 12a，我想提醒用户输入数字并继续输入数字，直到他们用完5个箭头。我哪里做错了？

var arrows = 5;
alert('You have ' + arrows + ' arrows!');
var shot    = prompt('How many arrows would you like to shoot?', '1');
var shotten  = parseInt(shot);

$('#12a').click(function(){
if(isNaN(shotten)){
    alert('You must enter a valid number of arrows!');
} else if(shotten > arrows){
    alert('Sorry, but there are only ' + arrows + ' arrows.  You can not shoot ' + shotten + ' arrows!');
} else if(shotten < 0){
    alert('Sorry, but you cannot shoot less than 0 arrows!');
} else {
    arrows -= shotten;
    alert('Now there are only ' + arrows + ' arrows!');
} 
});



  <p>There's a half-elf running at you. You can shoot him with your arrows if you'd like. </p>
  <p>
    <input type="submit" name="12a" id="12a" value="Let's do it.">
  </p>