body {

    padding: 10px;

}

​

a {

    position: relative;

    display: block;

    color: bule;

    font: 18px/3 sans-serif;

    text-decoration: none;

}

​

a[href^="http:"]:hover::before,

a[href^="https:"]:hover::before {

    content: "这是一个http链接";

    position: absolute;

    bottom: -16px;

    left: 10px;

    padding: 4px 5px;

    font: 14px/1.5 sans-serif;

    color: #ffcc00;

    background: #333;

    z-index: 10;

}

​

a[href^="https:"]:hover::before {

    content: "这是一个https链接";

}