Example:

This link will be highlighted when the mouse passes over it. 

<style type="text/css">
<!-- 
A:hover {background-color: orange} 
--> 
</style>
The link can also be highlighted at all times. Use the following code for this effect. 

<style type="text/css">
<!-- 
A:link {background-color: orange} 
--> 
</style>