Page.html

<!DOCTYPE html>
<html>
  <head>
    <base target="_top">
  </head>
  <body>
    <h1>Registrasi</h1>
    <label for="">Name: </label>
    <div class="form-group">
       <input type="text" id="username" name="username" placeholder="Username">
    </div>
    <div class="form-group">
       <input type="text" class="form-control" id="email" placeholder="Email">
    </div>
    <div class="form-group">
       <input type="text" class="form-control" id="name" placeholder="Name">
    </div>
    <div class="form-group">
       <input type="text" class="form-control" id="address" placeholder="Address">
    </div>
    <div>
       <button id="btn">Submit</button>
    </div>
    <script>
        document.getElementById('btn').addEventListener("click", doStuff);
        function doStuff() {
            var uname = document.getElementById("username").value;
            var name = document.getElementById("name").value;
            var email = document.getElementById("email").value;
            var address = document.getElementById("address").value;
            google.script.run.userClicked(uname, email, name, address);
            document.getElementById("username").value = "";
            document.getElementById("name").value = "";
            document.getElementById("email").value = "";
            document.getElementById("address").value = "";
        }
    </script>
  </body>
</html>