html5媒体属性问题

Question

下面这两个媒体属性值是否相同？如果不是每个人意味着什么？它们都有效吗？

<source src="music.mp3" media="screen, (color)">
<source src="music.mp4" media="screen and (color)">

Answer 1

http://dev.w3.org/csswg/css3-mediaqueries/

它们并不等同。逗号表示OR，而不是AND。查询中的and表示测试的两侧必须为true才能匹配。即：

screen, (color) = is a screen or anything that supports color
screen and (color) = is a color screen
projection, screen and (color) = is any type of projector OR a color screen