羊了个羊游戏

点击开始游戏按钮开始游戏，找到所有隐藏的羊儿并点击，不要点击其他物品。

<script>
	var score = 0;
	var totalSheep = 10;

	function startGame() {
		score = 0;
		totalSheep = 10;
		document.getElementById('scoreArea').innerHTML = '得分：' + score + ' / ' + totalSheep;
		document.getElementById('gameArea').innerHTML = '';
		for (var i = 0; i < totalSheep; i++) {
			var sheep = document.createElement('img');
			sheep.setAttribute('src', 'sheep.png');
			sheep.setAttribute('id', 'sheep' + i);
			sheep.setAttribute('class', 'sheep');
			sheep.style.position = 'absolute';
			sheep.style.top = Math.floor(Math.random() * 400) + 'px';
			sheep.style.left = Math.floor(Math.random() * 600) + 'px';
			sheep.onclick = function() {
				this.parentNode.removeChild(this);
				score++;
				document.getElementById('scoreArea').innerHTML = '得分：' + score + ' / ' + totalSheep;
				if (score == totalSheep) {
					alert('恭喜你找到了所有的羊儿！');
					endGame();
				}
			};
			document.getElementById('gameArea').appendChild(sheep);
		}
		document.getElementById('startBtn').disabled = true;
		document.getElementById('endBtn').disabled = false;
	}

	function endGame() {
		score = 0;
		totalSheep = 10;
		document.getElementById('scoreArea').innerHTML = '';
		document.getElementById('gameArea').innerHTML = '';
		document.getElementById('startBtn').disabled = false;
		document.getElementById('endBtn').disabled = true;
	}
</script>