vue后台系统实现全屏展示

<div class="header-user-con">
       <!-- 全屏显示 -->
       <div class="btn-fullscreen" @click="handleFullScreen">
           <el-tooltip effect="dark" :content="fullscreen?`取消全屏`:`全屏`" placement="bottom">
                <i class="el-icon-rank"></i>
           </el-tooltip>
        </div>
 </div>

     methods: {
          // 全屏事件
            handleFullScreen() {
                let element = document.documentElement;
                if (this.fullscreen) {
                    if (document.exitFullscreen) {
                        document.exitFullscreen();
                    } else if (document.webkitCancelFullScreen) {
                        document.webkitCancelFullScreen();
                    } else if (document.mozCancelFullScreen) {
                        document.mozCancelFullScreen();
                    } else if (document.msExitFullscreen) {
                        document.msExitFullscreen();
                    }
                } else {
                    if (element.requestFullscreen) {
                        element.requestFullscreen();
                    } else if (element.webkitRequestFullScreen) {
                        element.webkitRequestFullScreen();
                    } else if (element.mozRequestFullScreen) {
                        element.mozRequestFullScreen();
                    } else if (element.msRequestFullscreen) {
                        // IE11
                        element.msRequestFullscreen();
                    }
                }
                this.fullscreen = !this.fullscreen;
            }
      }