CSS "active" Selector

<div id="centeredmenu">

<ui>
<li><a href="menu1.html" class="active">menu1</a></li>
<li><a href="menu2.html">menu2</a></li>
<li><a href="menu3.html">menu3</a></li>
<li><a href="menu4.html">menu4</a></li>
</ui>
 </div>

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CSS

#centeredmenu ul li a.active,
#centeredmenu ul li a.active:hover {
   color:#fff;
   background:#000; /* change Hover Color? #6CF */
   font-weight:bold;
}



CSS "active" Selector
http://www.w3schools.com/cssref/sel_active.asp

The :active selector is used to select and style the active link.

A link becomes active when you click on it.

Tip: Use the :link selector to style links to unvisited pages, the :visited selector to style links to visited pages, and the :hover selector to style links when you mouse over them.

Note: :active MUST come after :hover (if present) in the CSS definition in order to be effective!