CSS has a property called content. It can only be used with the pseudo elements :after and :before. It is written like a pseudo selector (with the colon), but it’s called a pseudo element because it’s not actually selecting anything that exists on the page but adding something new to the page. This is what it looks like:
.email-address:before { content: "Email address: "; }
<ul> <li class="email-address">chriscoyier@gmail.com</li> </ul>
And the output would be like:
- Email address: chriscoyier@gmail.com
More examples here: http://css-tricks.com/css-content/