Edit in JSFiddle

<h2>This is an h2 element.</h2>

h2:before {
    content: "这是插入到h2前面的内容。";
    display: block;
    color: red;
}
h2:after {
    content: "这是插入到h2后面的内容。";
    display: block;
    color: blue;
}
}