1.
(1)HTML文件
<!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=utf-8" />
<title>选择器</title>
6 <link rel="stylesheet" type="text/css" href="style.css"/>
</head> <body>
<p> Specificity is determined by now specific the selector is.
<span id="specific"> A specific selector wins</span>
over a <span> more general one </span>.
</p> <p>
Order isn't important until there are one or more elememts of the same specificty referring to the same elememt.In
which case,<span> the last one wins</span>
</p> </body>
</html>
（2）CSS文件
@charset "utf-8";
/* CSS Document */ body {
font:Verdana, Geneva, sans-serif;
} span#specific {
background:pink;
} span {
background:red;
} span {
background:yellow;
}
这里CSS文件中有两个span{}，这两个选择器针对性都是1，因此后面的那个优先适用，这导致后面连个<span>元素都是黄色背景
效果图：
