title: HTML: Conditional submission of hidden input without JavaScript
body: <p>If I have a simple html form with two submit buttons:</p>
  
  <pre><code>&lt;form method="POST" class="submit_form main_form" action="myaction"&gt;
      &lt;input type="submit" name="goback" value="Go Back"  /&gt;
      &lt;input type="submit" name="confirm" value="Confirm"&gt;
      &lt;input type="hidden" name="secret" value="hello"/&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>It is possible to only post the hidden input if the "confirm" submit is clicked?</p>
  
  <p>If the "goback" submit is clicked the hidden input should be ignored.  I know how to accomplish this with JavaScript but was wondering if it can be done with just html.</p>
  
  <p>For anyone wondering, this is how you do this in JavaScript:</p>
  
  <pre><code>&lt;script&gt;
      var elements = document.getElementsByClassName('submit_form');
      elements[0].addEventListener(
          'submit', 
          function(event) {
              if(event.explicitOriginalTarget.name === 'goback'){
                  var hiddenInput = document.querySelector("input[name='step']");
                  hiddenInput.setAttribute("disabled", "disabled");
              }
          }
      );
  &lt;/script&gt;
  </code></pre>