控制是否全屏

// 全屏

      fullScreen(){

            var el = document.documentElement;

            var rfs = el.requestFullScreen || el.webkitRequestFullScreen || el.mozRequestFullScreen || el.msRequestFullscreen;      

                if(typeof rfs != "undefined" && rfs) {

                    rfs.call(el);

                };

              return;

        },

         //退出全屏

       exitScreen(){

            if (document.exitFullscreen) {  

                document.exitFullscreen();  

            }  

            else if (document.mozCancelFullScreen) {  

                document.mozCancelFullScreen();  

            }  

            else if (document.webkitCancelFullScreen) {  

                document.webkitCancelFullScreen();  

            }

            else if (document.msExitFullscreen) {  

                document.msExitFullscreen();

            }

            if(typeof cfs != "undefined" && cfs) {

                cfs.call(el);

            }

            this.$router.push({path: "/responseIndex"})

        },