Back button flat out refusing to work?

Back button flat out refusing to work?

So, here's the part of my head that loads jQuery, options and JQM:

  1.         <script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
  2.         <script>window.jQuery || document.write('<script src="<?php echo base_url();?>assets/js/vendor/jquery-1.9.1.min.js"><\/script>')</script>
  3.         <script src="<?php echo base_url();?>assets/js/options.js"></script>
  4.         <script src="http://code.jquery.com/mobile/1.3.1/jquery.mobile-1.3.1.min.js"></script>
And here's what goes into options: 


  1. $(document).bind("mobileinit", function() { 
  2. $.mobile.page.prototype.options.addBackBtn = true;
  3.     if (navigator.userAgent.indexOf("Android") != -1) { $.mobile.defaultPageTransition = 'none'; $.mobile.defaultDialogTransition = 'none'; } else {
  4.      $.mobile.defaultPageTransition = 'pop';
  5.     } 
  6. });
Yet the back button refuses to be added!! I have no idea what the problem is.  When typed in console, $.mobile.page.prototype.options.addBackBtn returns true.

What could be causing the issue?