if (e.which == 70)
{
        if(vid.requestFullScreen)
        {
            vid.requestFullScreen();
        }
...
else if (vid.mozRequestFullScreen)               // Firefox
        {
            vid.mozRequestFullScreen();
        }
...
if (vid.exitFullScreen && e.which == 70)
{
    vid.exitFullscreen();
}
else if (vid.cancelFullScreen && e.which == 70)              // Firefox
{
  vid.cancelFullScreen();
}
else if (vid.mozCancelFullScreen && e.which == 70)
{
  vid.mozCancelFullScreen();
}
else if (vid.webkitCancelFullScreen && e.which == 70)
{
  vid.webkitCancelFullScreen();
}