<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>RGBA Div Example</title>
<meta http-equiv="Content-type" content="text/html;charset=UTF-8">
<style type="text/css">
.alphaExample {background-color:rgba(32,128,27,.2);}
</style>
</head>
<body>
<div class="alphaExample">
<p>Sed dignissim lacinia nunc. Curabitur tortor. Pellentesque nibh. Aenean quam. In scelerisque sem at dolor. Maecenas mattis. Sed convallis tristique sem. Proin ut ligula vel nunc egestas porttitor. <i>Lorem ipsum dolor sit amet, consectetur adipiscing elit</i>. Morbi lectus risus, iaculis vel, suscipit quis, luctus non, massa. Fusce ac turpis quis ligula lacinia aliquet. Mauris ipsum. <b>Curabitur sodales ligula in libero</b>. Nulla metus metus, ullamcorper vel, tincidunt sed, euismod in, nibh. </p>
</div>
<p>Quisque volutpat condimentum velit. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Nam nec ante. Sed lacinia, urna non tincidunt mattis, tortor neque adipiscing diam, a cursus ipsum ante quis turpis. Nulla facilisi. <b>Proin ut ligula vel nunc egestas porttitor</b>. Ut fringilla. Suspendisse potenti. Nunc feugiat mi a tellus consequat imperdiet. Vestibulum sapien. Proin quam. Etiam ultrices. <b>Nam nec ante</b>. Suspendisse in justo eu magna luctus suscipit. </p>
</body>
</html>
For really old browsers you will want to include a fallback color.
Here's a workaround for older versions of IE.
Open in new window