index.html.erb

<% if params[:multi] %>
  <%= form_tag "/#{controller_name}/create_multi" do |f| %>
    <%= recaptcha_v3 action: 'demo_a' %>
    <%= recaptcha_v3 action: 'demo_b', external_script: false %>
    <%= submit_tag %>
  <% end %>

<% elsif params[:custom_callback] %>
  <script type="text/javascript">
    var myCallback = function(action, response) {
      alert(`Response for ${action} action: ${response}`);
    };
  </script>
  <%= recaptcha_v3 action: 'demo', callback: 'myCallback' %>

<% elsif params[:execute_on_submit] %>
  <%= form_tag "/#{controller_name}" do %>
    <%= recaptcha_v3 action: 'demo' %>
    <%= submit_tag %>
  <% end %>

  <script type="text/javascript">
    const form = document.forms.item(0)
    const hiddenInput = document.getElementById('g-recaptcha-response-demo')
    form.addEventListener('submit', async function(e) {
      e.preventDefault();
      console.log('Submitted form. Getting fresh reCAPTCHA response token…')
      const response = await window.executeRecaptchaForDemoAsync()
      console.log(`Response was: ${response}`)
      hiddenInput.value = response
      form.submit()
    });
  </script>

<% else %>
  <%= form_tag "/#{controller_name}" do %>
    <%= recaptcha_v3 action: 'demo' %>
    <%= submit_tag %>
  <% end %>
<% end %>

<%= link_to 'Single', '?' if params[:multi] || params[:custom_callback] || params[:execute_on_submit] %>
<%= link_to 'Multi',             '?multi=1'             unless params[:multi] %>
<%= link_to 'Custom callback',   '?custom_callback=1'   unless params[:custom_callback] %>
<%= link_to 'Execute on submit', '?execute_on_submit=1' unless params[:execute_on_submit] %>