if (document.exitFullScreen) {

         document.exitFullScreen()

       } else if (document.mozCancelFullScreen) {

         document.mozCancelFullScreen()

       } else if (document.webkitExitFullscreen) {

         document.webkitExitFullscreen()

       } else if (document.msExitFullscreen) {

         document.msExitFullscreen()

       }

//这样退出全屏，video标签白屏，有声音，安卓机型此现象必现。。

//