toggle-fullscreen.jquery.js

$(function() {
  $.fn.toggleFullscreen = function() {
    var elem = this[0];
    if (!document.fullscreenElement && !document.mozFullScreenElement && !document.webkitFullscreenElement && !document.msFullscreenElement ) {
      if (elem.requestFullscreen) {
        elem.requestFullscreen();
      } else if (elem.msRequestFullscreen) {
         elem.msRequestFullscreen();
      } else if (elem.mozRequestFullScreen) {
        elem.mozRequestFullScreen();
      } else if (elem.webkitRequestFullscreen) {
        elem.webkitRequestFullscreen(Element.ALLOW_KEYBOARD_INPUT);
      } else {
        return $(this)
      }
    } else {
      if (document.exitFullscreen) {
        document.exitFullscreen();
      } else if (document.msExitFullscreen) {
        document.msExitFullscreen();
      } else if (document.mozCancelFullScreen) {
        document.mozCancelFullScreen();
      } else if (document.webkitExitFullscreen) {
        document.webkitExitFullscreen();
      }
    }
    return $(this);
  }
  $(document).on('webkitfullscreenchange mozfullscreenchange fullscreenchange MSFullscreenChange', function() {
    var fullscreenElement = document.fullscreenElement || document.mozFullScreenElement || document.webkitFullscreenElement;
    if (fullscreenElement) {
      $(fullscreenElement).addClass('fullscreen')
    } else {
      $('.fullscreen').removeClass('fullscreen')
    }
  });
})