Tools/TestWebKitAPI/Tests/WebKit2/associate-form-controls.html

<html>
<head>
  <script>
    function addForm()
    {
        var form = document.createElement("form");
        form.id = "login_form";

        var usernameField = document.createElement("input");
        usernameField.id = "username";
        usernameField.type = "text";
        form.appendChild(usernameField);

        document.body.appendChild(form);
    }

    function addPasswordFieldToForm()
    {
        var passwordField = document.createElement("input");
        passwordField.id = "password";
        passwordField.type = "password";

        var form = document.getElementById("login_form");
        form.appendChild(passwordField);
    }
  </script>
</head>
<body onload="addForm()">
<button onclick="addPasswordFieldToForm()">Manual Testing: Add the password field</button>
</body>
</html>