让IE浏览器支持RGBA颜色
http://www.hujuntao.com/web/css/ie-browser-support-for-rgba-color.html
透明纯色背景
background: #000;
opacity: .8; /* 非 IE */
filter: alpha(opacity=80); /* IE */
/* 全部透明了 */
background: rgba(0,0,0,0.8); /* 非 IE */
filter: progid:DXImageTransform.Microsoft.gradient(enabled='true',startColorstr='#CC000000', endColorstr='#CC000000'); /* IE */
/* 背景透明只 */
CSS 背景颜色属性值转换
http://www.linxz.de/demo/hex_color.html
图片透明度变化
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<title></title>
<style>
.hover {
opacity: .8;
filter: alpha(opacity=80);
}
</style>
</head>
<body>
<img onmousemove="this.className='hover'" onmouseout="this.className=''" src="http://29293.pic.baomihua.com/pic/5103065105981035073.jpg" width="392" height="220" alt="春哥">
</body>
</html>
IE6 支持透明 png
_background: none;
_filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled='true', sizingMethod='scale', src='xxx.png');