You can use the title attribute to add a small box that will display information when a visitor's mouse is left over a hypertext link .
Also if you leave your mouse over the following link back to HTML lesson main page,you will get a message.
The way you include this sort of message in a link is to do the link in this way with a "title variable":
<a href ="footer.txt" title="This will return you to the HTML Lesson Main Page" >index.html </a>