<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<div style='width:30%;height:600px'>
<svg viewBox="0,0,640,480" >
<rect x="0" y="0" width="100%" height="100%" fill="green"/>
<rect x="10" y="10" width="100" height="100" fill="orange" />
<rect x="200" y="300" width="90" height="90" fill="orange" />
<circle id='eyunxiaojie' cx="400" cy="1500" r="50" fill="gray" />
</svg>
</div>
</body>
</html>
viewBox的四个参数分别代表：最小X轴数值；最小y轴数值；宽度；高度。
