SOURCE

<ul>
    <li><a href="http://example.com/html/h5">HTML5+CSS3权威指南</a></li>
    <li><a href="http://example.com/js/jsapd">JavaScript高级程序设计</a></li>
    <li><a href="http://example.com/html/h5dg">权威指南</a></li>
    <li><a href="http://example.com/js/jsapd">JavaScript权威指南第7版</a></li>
</ul>

* {
    color:gray;
}
li:nth-child(2n+1)::after {
    content:"[HTML]" ;
    font-size:0.5em;
    color:blue;
}
li:nth-child(2n)::after {
    content:"[JavaScript]";
    font-size:0.5em;
    color:red;
}