title: Bootstrap 3: Form "required" not working in mobile devices
body: <p>I'm working on a form I styled with bootstrap and connected to google docs doing a little hack. 
  The form works great when I test it in the browser and the developer tools emulators. If I leave a blank space, a small pop tells me to fill that space before continuing and it doesn't post the information into the spreadsheet nor advancing to the greeting page (expected behavior).</p>
  
  <p>However when I test this in my iPhone and other mobile devices it doesn't work. I can leave blank spaces and it just simply ignores the "required" condition and it takes me to the greeting pages.</p>
  
  <p>As you can see that's a problem. I want the form to behave as it behaves on the browser. Any ideas?</p>
  
  <pre><code>&lt;!-- Form --&gt;
  &lt;div class="col-lg-6 form-container" style="margin-top: 20px; margin-left:-20px"&gt;
  &lt;script type="text/javascript"&gt;var submitted=false;&lt;/script&gt;
      &lt;iframe name="hidden_iframe" id="hidden_iframe"
      style="display:none;" onload="if(submitted)
      {window.location='thank-you.html';}"&gt;&lt;/iframe&gt;
      &lt;form class="form-horizontal" action="https://docs.google.com/a/xxxxxxxx.com/forms/d/1psz4JlSVCmr99r7Qdg0LsV0WJjwzm1aSZBECmWpFX-w/formResponse" method="post"
      target="hidden_iframe" onsubmit="submitted=true;"&gt;
  &lt;fieldset&gt;
  
  &lt;!-- Form Name --&gt;
  &lt;h3 class="centered"&gt;&lt;span class="glyphicon glyphicon-ok"&gt;&lt;/span&gt; Get Your API Key Today&lt;/h3&gt;
  
  &lt;!-- Text input--&gt;
  &lt;div class="form-group"&gt;
    &lt;label class="col-md-4 control-label" for="Full Name"&gt;Full Name*&lt;/label&gt;  
    &lt;div class="col-md-4"&gt;
    &lt;input type="text" name="entry.492241038" value="" class="form-control input-md required" id="entry_492241038" dir="auto" aria-label="1  " aria-required="true" required="" title=""&gt;
  
    &lt;/div&gt;
  &lt;/div&gt;
  
  &lt;!-- Text input--&gt;
  &lt;div class="form-group"&gt;
    &lt;label class="col-md-4 control-label" for="Company"&gt;Company*&lt;/label&gt;  
    &lt;div class="col-md-4"&gt;
    &lt;input type="text" name="entry.22144039" value="" class="form-control input-md required" id="entry_22144039" dir="auto" aria-label="2  " aria-required="true" required="" title=""&gt;
  
    &lt;/div&gt;
  &lt;/div&gt;
  
  &lt;!-- Text input--&gt;
  &lt;div class="form-group"&gt;
    &lt;label class="col-md-4 control-label" for="Company Email"&gt;Company Email*&lt;/label&gt;  
    &lt;div class="col-md-4"&gt;
    &lt;input type="text" name="entry.1882859742" value="" class="form-control input-md required" id="entry_1882859742" dir="auto" aria-label="3  " aria-required="true" required="" title=""&gt;
  
    &lt;/div&gt;
  &lt;/div&gt;
  
  &lt;!-- Text input--&gt;
  &lt;div class="form-group"&gt;
    &lt;label class="col-md-4 control-label" for="Phone Number"&gt;Phone Number*&lt;/label&gt;  
    &lt;div class="col-md-4"&gt;
    &lt;input type="text" name="entry.1063706991" value="" class="form-control input-md required" id="entry_1063706991" dir="auto" aria-label="4  " aria-required="true" required="" title=""&gt;
  
    &lt;/div&gt;
  &lt;/div&gt;
  
  &lt;!-- Textarea --&gt;
  &lt;div class="form-group"&gt;
    &lt;label class="col-md-4 control-label" for="How will you use the API?"&gt;How will you use the API?*&lt;/label&gt;
    &lt;div class="col-md-4"&gt;                     
    &lt;textarea name="entry.1508475478" rows="3" cols="0" class="form-control input-md required" id="entry_1508475478" dir="auto" aria-label="5  " aria-required="true" required=""&gt;&lt;/textarea&gt;
    &lt;/div&gt;
  
  &lt;/fieldset&gt;
  &lt;div class="submit-button centered"&gt;
      &lt;!-- &lt;input type="submit" name="submit" value="Submit" id="ss-submit"&gt; --&gt;
      &lt;button href="thank-you.html" class="btn btn-info btn-lg btTxt submit" id="ss-submit" name="submit" type="submit" value="Submit"&gt; Get Started Now &lt;/button&gt;
  &lt;/div&gt;
  &lt;/form&gt;
  
  &lt;/div&gt;
  </code></pre>