div全屏和退出全屏

<div id="contain"></div>
JavaScript：
<button  οnclick="showFullScreen()">dom全屏</button>
<button  οnclick="exitFullScreen()">退出全屏</button>
vue:
<button  @click="showFullScreen()">全屏</button>
<button  @click="exitFullScreen()">退出全屏</button>

function showFullScreen(){
    var full=document.getElementById("contain");
    launchIntoFullscreen(full);
}
function exitFullScreen() {
     exitFullscreen();
}

//div标签全屏方法
function launchIntoFullscreen(element) {
    if(element.requestFullscreen){
        element.requestFullscreen();
    } else if(element.mozRequestFullScreen) {
        element.mozRequestFullScreen();
    } else if(element.webkitRequestFullscreen) {
        element.webkitRequestFullscreen();
    } else if(element.msRequestFullscreen) {
        element.msRequestFullscreen();
    }
}
//退出div标签全屏方法
function exitFullscreen() {
    if(document.exitFullscreen) {
        document.exitFullscreen();
    } else if(document.mozCancelFullScreen) {
        document.mozCancelFullScreen();
    } else if(document.webkitExitFullscreen) {
        document.webkitExitFullscreen();
    }
}