<!DOCTYPE html>
<html>
<head>
<style>
img
{
opacity:0.4;
filter:alpha(opacity=40); /* For IE8 and earlier */
}
img:hover
opacity:1.0;
filter:alpha(opacity=100); /* For IE8 and earlier */
</style>
</head>
<body>
<h1>图像透明度</h1>
<img src="/img/tulip_peach_blossom_s.jpg" alt="Peach Blossom" />
<p><b>注释：</b>在 IE 中，必须添加 <!DOCTYPE>，这样才能将 :hover 选择器用于除了 <a> 之外的其它元素。</p>
</body>
</html>