views/signup.erb
<!doctype html>
<html lang="ja">
<head>
<meta charset="utf-8">
<title>OpenYo</title>
<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
</head>
<body>
<h1>Sign Up</h1>
<span id="head">If you have account already, login <a href="/login/">HERE</a></span>
<p>
id: <input type="text" id="id" size="20" /><br />
pass: <input type="password" id="pass" /><br />
<input type="submit" id="create" value="create" /><br />
<span id="msgBox"></span><br />
</p>
</body>
<script src="/js/signup.js"></script>
</html>