% layout 'default';
% title 'test';
<h1>test page</h1>
<% if ($method eq 'POST') { %>
<p><%= $string %></p>
<% } else { %>
<form action="/test" method="post">
  <label>Give me string:<br>
    <input type="text" name="string"></label><br>
  <br>
  <input type="submit" value="Submit">
</form>
<% } %>