title: window.open does not work correctly in firefox
body: <p>I have this form: </p>
  
  <pre><code>&lt;form id="platba"&gt;
               &lt;label class="c-input c-radio"&gt;
                &lt;input id="radio1" name="radio" type="radio" value="https://www.paypal.com/uk/webapps/mpp/home"&gt;
                &lt;span class="c-indicator"&gt;&lt;/span&gt;
                &lt;img src="img/payments/paypal.png" width="80" style="margin-top:-5px"&gt;&amp;nbsp Paypal
              &lt;/label&gt;
               &lt;br /&gt;
               &lt;br /&gt;
              &lt;label class="c-input c-radio"&gt;
                &lt;input id="radio2" name="radio" type="radio" value="http://www.mbank.cz/osobni/"&gt;
                &lt;span class="c-indicator"&gt;&lt;/span&gt;
                &lt;img src="img/payments/mbank.png" width="80" style="margin-top:-5px"&gt;&amp;nbsp mBank
              &lt;/label&gt;
               &lt;br /&gt;
               &lt;br /&gt;
              &lt;label class="c-input c-radio"&gt;
                &lt;input id="radio2" name="radio" type="radio" value="http://example.com/platebnikarta"&gt;
                &lt;span class="c-indicator"&gt;&lt;/span&gt;
                &lt;img src="img/payments/visa_mastercard.png" width="80" style="margin-top:-5px"&gt;&amp;nbsp Platební karta
              &lt;/label&gt;
              &lt;hr&gt;            
  
              &lt;button type="submit" class="btn btn-primary"&gt;Pokračovat v placení&lt;/button&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>And at the end of the file i have javascript which open new window based on radio button selection:</p>
  
  <pre><code>$(document).ready(function(){
        $("#platba").submit(function(){
          event.preventDefault();
          var loc = $('input[name="radio"]:checked').val();
          window.open(loc,'_blank');
          //self.close ();
        });
  
      });
  </code></pre>
  
  <p>It is working fine in Google Chrome and IE, but in firefox it just add the value of radio button into the adressbar.
  Example:</p>
  
  <pre><code>http://something/something/something/something.php?radio=https%3A%2F%2Fwww.paypal.com%2Fuk%2Fwebapps%2Fmpp%2Fhome
  </code></pre>