1、问题：P标签嵌套P标签时出现错误
案发现场：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div>
<p>p1</p>
<p><p>p2</p></p>
</div>
<p>p3</p>
</body>
<script src="jquery-1.8.3.min.js"></script>
<!-- <script src="jquery-1.9.1.min.js"></script> -->
<script type="text/javascript">
$(function(){
$("div > p").css({
"color": "red",
})
});
</script>
</html>
结论：p标签里面不能嵌套块级元素。
验证：通过
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
*{
color: red;
}
</style>
</head>
<body>
<div>
<span>span1</span>
<span>
span2
<span>span3</span>
</span>
</div>
</body>
<script src="jquery-1.8.3.min.js"></script>
<!-- <script src="jquery-1.9.1.min.js"></script> -->
<script type="text/javascript">
$(function(){
$("div > span").css({
"color": "blue",
})
});
</script>
</html>