如何使用js全屏事件？

// 全屏
function qp() {
  var de = document.documentElement;
  if (de.requestFullscreen) {
    de.requestFullscreen();
  } else if (de.mozRequestFullScreen) {
    de.mozRequestFullScreen();
  } else if (de.webkitRequestFullScreen) {
    de.webkitRequestFullScreen();
  }
  $("#bre").css("display","none")
  $("#bres").css("display","block")
}

function tcqp(){
    $("#bre").css("display","block")
      $("#bres").css("display","none")
    if (document.exitFullscreen) {
      document.exitFullscreen();
      console.log(1);
    } else if (document.mozCancelFullScreen) {
      document.mozCancelFullScreen();
      console.log(2);
    } else if (document.webkitExitFullscreen) {
      document.webkitExitFullscreen();
      console.log(3);
    }
}