cannot close menu when changing page : i just created a new page, valid only for devices 

    right now i tested only for android, ios in the future

You can take a look at this page here : [http://www.suale.it/prova/cqc/index.html][1]
<br>The main problem, is that every time i change page in the menu, it does not collapse itself.<br>
I tried with this code in the **quiz.js** file to collapse the menu,
but has no effect:

     var x = document.getElementById("myTopnav");
        x.className = "topnav";

what can i do?


  [1]: http://www.suale.it/prova/cqc/index.html