<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>Fallback content</title>
</head>
<body>
<canvas id="myCanvas" width="300" height="150">
Fallback content, in case the browser does not support Canvas.
</canvas>
</body>
</html>
浏览后，显示 Fallback content, in case the browser does not support Canvas.
答案
支持的，请注明文档定义
<!DOCTYPE HTML>