demo html文件 (原模原样,复制粘贴即可使用)
<!DOCTYPE>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>CanvasDemo</title>
</head>
<body>
<div id="cas" style="position: absolute;width: 200px;height: 200px; left: 200px; z-index: 99999;"></div>
<script src="https://cdn.bootcss.com/canvas-nest.js/2.0.4/canvas-nest.js" type="text/javascript" color="255,0,0" opacity="0.5" count="200" ></script>
</body>
</html>