diff --git a/app/views/home/demo.html.erb b/app/views/home/demo.html.erb
index 8b86836..c810740 100644
--- a/app/views/home/demo.html.erb
+++ b/app/views/home/demo.html.erb
@@ -3,6 +3,7 @@
     <div class="columns">
       <div class="column is-one-third">
         <form class="form demo-form" id="demo-form" action="<%= submission_url(DEMO_FORM) %>" method="POST" enctype="multipart/form-data" data-tinyforms="true">
+          <input type="hidden" name="ID" value="tinyforms_id">
           <h3>Demo</h3>
           <p>
             This short form is connected to the embedded <%= link_to 'document', DEMO_FORM.google_spreadsheet_url %> on the right. <br>