都知道，在alpha滤镜下，背景透明了，里面的文字也会跟随透明，我们可以设置内容的position为relative可以解决这个问题
但是在position为absolute这么做却没有效果，怎么解决呢，看代码：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gbk" />
<title>alpha</title>
<style type="text/css">
.alpha
{
100px;
height:100px;
background-color:red;
display:block;
opacity: 0.35;
filter: "alpha(opacity=35)";
filter: alpha(opacity=35);
-moz-opacity: 0.35;
}
</style>
</head><body>
<div class="alpha">
<div>文字显示</div>
</div>
</body>
</html>
这样显示的文字也是0.35的透明，修改代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gbk" />
<title>alpha</title>
<style type="text/css">
.alpha
{
100px;
height:100px;
background-color:red;
display:block;
opacity: 0.35;
filter: "alpha(opacity=35)";
filter: alpha(opacity=35);
-moz-opacity: 0.35;
}
</style>
</head>
<body>
<div class="alpha">
<div style="position:relative;"> 文字显示</div>
</div>
</body>
</html>
文字没有了不透明效果
这没什么，也不是我要说的重点
看这个
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<style type="text/css">
.alpha50
{
opacity: 0.5;
filter: "alpha(opacity=50)";
filter: alpha(opacity=50);
-moz-opacity: 0.5;
}
.box
{
173px;
height: 163px;
display: block;
background-color: orange;
}
.absolute
{
position: absolute;
173px;
height: 30px;
margin-top: 133px;
}
.relative
{
position: relative;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<div>
<div class="box">
<div class="absolute alpha50">
<div class="relative">显示文字</div>
</div>
</div>
</div>
</form>
</body>
</html>
虽然设了relative，但文字还是透明的
反复试验 我发现修改代码顺序可以解决这个问题
如下：
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<style type="text/css">
.alpha50
{
opacity: 0.5;
filter: "alpha(opacity=50)";
filter: alpha(opacity=50);
-moz-opacity: 0.5;
}
.box
{
173px;
height: 163px;
display: block;
background-color: orange;
}
.absolute
{
position: absolute;
173px;
height: 30px;
margin-top: 133px;
}
.relative
{
position: relative;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<div>
<div class="box">
<div class="absolute">
<div class="alpha50">
<div class="relative">显示文字</div>
</div>
</div>
</div>
</div>
</form>
</body>
</html>
先absolute再alpha可以解决在absolute下设置relative的不透明度
ok