<style> a { position: relative; display: inline-block; outline: none; text-decoration: none; color: #000; font-size: 32px; padding: 5px 5px; } a:hover::before, a:hover::after { position: absolute; } a:hover::before { content: "["; left: -20px; } a:hover::after { content: "]"; right: -10px; } </style>
当鼠标在a元素停留,会动态显示 [ ]