动态效果如图： 可以通过点击按钮，或者esc键实现全屏和退出全屏的效果

 实现代码：

<template>
    <div class="hello">
        <el-button @click="fullScreen()" v-if="!isFullscreen">查看全屏</el-button>
        <el-button @click="fullScreen()" v-else>退出全屏</el-button>
    </div>
</template>

<script>
export default {
    name: 'HelloWorld',
    created() {
        document.addEventListener('fullscreenchange', () => {
            this.$nextTick(() => {
                // 这里对全屏后样式进行操作
                this.isFullscreen = !this.isFullscreen;
            });
        });
    },
    data() {
        return {
            isFullscreen: false
        };
    },
    methods: {
        fullScreen() {
            /*判断是否全屏*/
            let isFullscreen =
                document.fullScreenElement || //W3C
                document.msFullscreenElement || //IE
                document.mozFullScreenElement || //火狐
                document.webkitFullscreenElement || //谷歌
                false;
            if (!isFullscreen) {
                let el = document.documentElement;
                if (el.requestFullscreen) {
                    el.requestFullscreen();
                } else if (el.mozRequestFullScreen) {
                    el.mozRequestFullScreen();
                } else if (el.webkitRequestFullscreen) {
                    el.webkitRequestFullscreen();
                } else if (el.msRequestFullscreen) {
                    el.msRequestFullscreen();
                }
                console.log('切换到了全屏');
            } else {
                if (document.exitFullscreen) {
                    document.exitFullscreen();
                } else if (document.msExitFullscreen) {
                    document.msExitFullscreen();
                } else if (document.mozCancelFullScreen) {
                    document.mozCancelFullScreen();
                } else if (document.webkitCancelFullScreen) {
                    document.webkitCancelFullScreen();
                }
                console.log('退出了全屏');
            }
        }
    }
};
</script>

<style scoped>
</style>