js vue 浏览器全屏

if(this.$data.isfullscreen){
                    this.$data.isfullscreen = false
                    document.exitFullscreen()
                    return
                }
                this.$data.isfullscreen = true
                var box=document.documentElement
                         if(box.requestFullscreen){
                             box.requestFullscreen()
                         }else if(box.webkitRequestFullscreen){
                             //谷歌浏览器
                             box.webkitRequestFullscreen()
                         }else if(box.mozRequestFullScreen){
                             //火狐浏览器
                             box.mozRequestFullScreen()
                         }else if(box.msRequestFullscreen){
                              //IE浏览器
                             box.msRequestFullscreen()
                         }else{
                             alert('你的浏览器版本太低！')
                         }