In an AMT HTML Questio. for batch, how to generate all inputs

Question

So I've been trying to generate the contents mturk_form using the DOM model for a Amazon Mechanical Turk HTML question. I ran into an interesting error when I generated ALL inputs using the script: I get the error Dhtml template must contain a question.

This error can be hacked around by putting an unnamed hidden input in the top of the page, like the example below. Remove the <input type="hidden" /> and the error comes back. Does anyone have a better way?

    <p><input type="hidden" /> <script>
    window.onload = create_form;
    function validate()
    {

      var checkbox = document.getElementById("testbox");
      if (checkbox.checked)
      {
        return true;
      }
      else
      {
        alert("failed validation");
        return false;
      }
    }
    function create_form()
    {
    var turkform = document.forms[0];
    var testbox = document.createElement('input');
    testbox.type="checkbox";
    testbox.name="testbox";
    testbox.id="testbox";
    testbox.innerHTML="check to be valid";
    turkform.appendChild(testbox);
    turkform.appendChild(document.createTextNode('check to be valid'));
    var submitbutton = document.getElementById("submitButton");
    submitbutton .onclick=validate;
    turkform.appendChild(submitbutton);
    }

    </script></p>