How can I disable all keyboard keys, but Esc, in Full Screen Mode?

JavaScript
1

hi,
i have a page that goes full screen when loaded. i want it to stay that way - until the esc key is pressed.
the thing is - some of the keys are still working: F!, F5, F11, F12 and the windows key.
i also want - if that’s possible - do disable the right mouse button

<body onclick="myFunction()" onkeydown="myFunction()">

<script>
   var news=0; // to check if new page load -> to go to full screen

   function myFunction() {   
      // GO TO FULL SCREEN ON PAGE LOAD (OR REFRESH)
      if (news==0) {
         var elem = document.documentElement;
         if (elem.requestFullscreen) {
            elem.requestFullscreen();
         } else if (elem.msRequestFullscreen) {
            elem.msRequestFullscreen();
         } else if (elem.mozRequestFullScreen) {
            elem.mozRequestFullScreen();
         } else if (elem.webkitRequestFullscreen) {
            elem.webkitRequestFullscreen();
         }
         news = 1; 
      }

      // give the body a new random color
      var letters = '0123456789ABCDEF';
      var color = '#';
      for (var i = 0; i < 6; i++ ) {
         color += letters[Math.floor(Math.random() * 16)];
      }
      document.body.style.backgroundColor = color;

   }
</script>
</body>