mermaidでシーケンス図

<!Doctype html>
<html>
<head>
    <meta charset="UTF-8">
</head>
<body>
    <div class="mermaid">
      sequenceDiagram
        A ->> B :要求
        B -->> A: 返答
    </div>
    <script src="https://unpkg.com/mermaid/dist/mermaid.min.js"></script>
    <script>
      mermaid.initialize({
        startOnLoad:true
      });
    </script>
</body>
</html>

よくできてんなー