title: Form submit button is not working sometimes
body: <p>I have developed a quiz module in which whenever the user clicks on <code>submit</code> button, the button gets <code>disabled</code> and then redirected to next question.</p>
  
  <p>Now the problem is sometimes the <code>submit</code> button doesn't respond for about 4-5 or more clicks and then suddenly submits the form which results in skipping of 4-5 questions. Have tried using <code>document.form.submit</code> and even <code>jQuery('#question_form').submit()</code>. But still few users report the same problem.</p>
  
  <p>I am unable to create the same scenario for myself.</p>
  
  <p>In my view page I have: </p>
  
  <pre><code>   &lt;form id="question_form" style="text-align:center;" name="question_form" method="post" action="/exam/259/calc_current_score?name=question" accept-charset="UTF-8"&gt;
      &lt;!-- some fields to be submitted --&gt;
      &lt;input type="submit" value="Submit" onclick="changeButtonText(event,this.form);" name="submit_button" id="submit_button" class="exam-btn-primary"&gt;
  
      &lt;/form&gt;
  
     &lt;script type="text/javascript"&gt;
      function changeButtonText(e,form){
  
  //if validation is true then it submits the form like this
          error_notification.style.display="none";
          form.submit();
          jQuery('#submit_button').css({'background-color':'#C3CACD'});
          form.submit_button.disabled=true;
          return true;
  
  //else if the validation fails then 'submit button' is not disabled
          e.preventDefault();
      }
      &lt;/script&gt;
  </code></pre>
  
  <p>So, the main problem is that even when the user clicks on the submit button after selecting an option neither the form gets submitted (which would eventually redirect to the next page) nor the button gets <code>disabled</code> (also the color of the button changes when validations are successful) so they keep clicking and this mostly happens in <code>Google Chrome</code>. I don't know that is it because of slow net connection or the resources are taking longer time to load.</p>
  
  <p>Users report that sometimes they have to click multiple number of times in order to submit the question's answer, and whenever they click multiple number of times the questions get skipped. For example if they click <code>x</code> times on <code>submit button</code> they move forward by <code>x</code> questions and they are unable to score because of that.</p>