CSS3 RGBA color
Detailed explanation of RGBA color value of CSS3:
This chapter will introduce the usage of RGBA color value. You must feel very familiar with it. This is because everyone is very familiar with RGB, but An additional A is added at the end.
Grammar structure:
RGBA(R,G,B,A)
Parameter analysis:
R(red ): red value. Positive integer | Percent.
G(green): Green value. Positive integer | Percent.
B(blue): Blue value. Positive integer | Percent.
A(Alpha): Alpha transparency, value between 0 and 1.
RGBA is based on RGB and adds a parameter to control alpha transparency. The positive integer values of the three parameters R, G, and B are 0-255, and the percentage value is 0.0% - 100.0%. Values outside the range will be Up to its nearest value limit, the value of parameter A is between 0 and 1. It is important to note that not all browsers support percentage parameter values.
Browser compatibility:
The RGBA color value compatibility is pretty good. It is not supported by IE8 and browsers below IE8, but is supported by other standard browsers.
Code example:
<!DOCTYPE html>
<html>
<head>
<meta charset=" utf-8">
<meta name="author" content="http://ask.php.cn/" />
<title>CSS3教程</title>
<style type="text/css">
.first{color:rgba(128,128,128,0.2);}
.second{color:rgba(50%,50%,50%,0.3);}
.third{color:rgba(160,100,150,0.6);}
</style>
</head>
<body>
<div class="first">php中文网欢迎您</div>
<div class="second">php中文网欢迎您</div>
<div class="third">php中文网欢迎您</div>
</body>
</html> 
