执行下面代码即可：

let value = false
function handleFullscreen () {
      let main = document.body
      if (this.value) {
        if (document.exitFullscreen) {
          document.exitFullscreen()
        } else if (document.mozCancelFullScreen) {
          document.mozCancelFullScreen()
        } else if (document.webkitCancelFullScreen) {
          document.webkitCancelFullScreen()
        } else if (document.msExitFullscreen) {
          document.msExitFullscreen()
        }
      } else {
        if (main.requestFullscreen) {
          main.requestFullscreen()
        } else if (main.mozRequestFullScreen) {
          main.mozRequestFullScreen()
        } else if (main.webkitRequestFullScreen) {
          main.webkitRequestFullScreen()
        } else if (main.msRequestFullscreen) {
          main.msRequestFullscreen()
        }
      }
    }