<html>
<head></head>
<body>
<div style="border:2px solid white;width:400px;height:100%;background:url(http://www.oisix.com/gift/image/00005783-300-1.jpg) top left repeat-x;">
<div style="border:2px solid white;width:200px;height:275px;margin-right:0px;padding:0px;color:#366;background:white;float:right;filter:alpha(opacity=50);-moz-opacity:.50;opacity:.50;font-family:Verdana, Arial, Helvetica;font-size: 28px;line-height:26px;text-align:right;">
<b>this text is</b>
in the second div <b>with bold</b> and plain text
<b>over the image with an </b>
opaque background
</div>
</div>
<div style="clear:both;"></div>
</body>
</html>
参考：http://www.mandarindesign.com/opacity.html
