$("ul li:nth-child(4)").css("color", "red");//将ul元素下的第5个元素的文本颜色设置为红色，即该li元素的索引值为4
<!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>子元素过滤选择器</title>
<script type="text/javascript" src="jquery-1.7.min.js"></script>
<script type="text/javascript">
$(document).ready(function() {
$("table tr:first-child").css("background", "#FCF");
$("table tr:last-child").css("background", "yellow");
$("tr td:nth-child(even)").css("border", "1px solid red");
$("div h3:only-child").css("color", "#999");
});
</script>
</head>
<body>
<div align="center">子元素过滤器应用实例</div>
<table width="462" height="152" border="1">
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
</table>
</body>
</html>
