为什么我的有点不一样？（这里我是复制来的 没有写在一起）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>五子棋</title>
<link type="text/css" rel="stylesheet" href="css/style.css"/>
</head>
<body>
<canvas id="chess">该浏览器不支持canvas画布</canvas>
<script type="text/javascript" src="js/script.js"></script>
</body>
</html>
var chess = document.getElementById('chess');
var context = chess.getContext('2d');
context.strokeStyle = '#bfbfbf';
context.moveTo(0, 0);
context.lineTo(450, 450);
context.stroke();
#chess {
display: block;
width: 450px;
height: 450px;
margin: 50px auto;
box-shadow: 5px 5px 5px #b9b9b9, -2px -2px 2px #efefef;
}
下面是我浏览器中显示的
