显示标签基本轮廓

// 请实现，鼠标移到页面中的任意标签，显示出这个标签的基本矩形轮廓。

export {};

function borderDom(d: HTMLElement) {
d.onmouseover = function(e) {
this.style.border = '1px solid red';
};
d.onmouseout = function(e) {
this.style.border = '';
}
}

function borderDomTree(dom: HTMLElement) {
borderDom(dom);

Array.from(dom.childNodes).forEach(d => {
if (d.nodeType === 1) {
borderDomTree(d as HTMLElement);
}
});
}