console 命令行工具 X clear
console
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>div盒子</title>
    <style>
        div{
            height:200px;
            width:200px;
            border:1px solid;
        }
    </style>
</head>
<body>
<div>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
   <circle cx="100" cy="50" r="40" stroke="black" stroke-width="2" fill="red" />
</svg> 
</div>
</body>
</html>