<!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" />
<script type="text/javascript" src="jquery-1.7.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("form input").css("color", "red"); //给form元素的后代input元素设置字体颜色
$("div>div").css("background", "#FCF"); //给maindiv下的子元素div1和div2设置背景颜色
$("div~input").css("border", "2px solid blue"); //给div元素后面的所有input元素设置边框
$("div+input").css("border", "2px solid red"); //给紧跟在div元素后的input元素设置边框
});
</script>
<title>层级选择器</title>
</head>
<body>
<form id="form1">
<label>form元素的后代input元素为:input1, input2, input3</label>
<input type="text" id="input1" value="文本框1" />
<div id="maindiv">
<div id="div1">maindiv的子元素:id为div1</div>
<div id="div2">maindiv的子元素:id为div2</div>
</div>
<input type="text" id="input2" value="文本框2" />
<input type="text" id="input3" value="文本框3" /><br />
<label>maindiv的所有子元素为:div1, div2</label>
</form>
</body>
</html>