<html>
<head>
<script src="https://libs.baidu.com/jquery/1.10.2/jquery.min.js">
</script>
<script>
$(document).ready(function(){
$("div span").css("background-color","yellow");
});
</script>
</head>
<body>
<h2>看看 $("div span") 会选中哪一部分呢?</h2>
<h4>This div element has two descendants, p and span:</h4>
<div style="border:1px solid black;padding:10px;">
<p>This is a paragraph.</p>
<span>This is a text inside a span.</span>
</div>
<h4>This div element has also two descendants, p and span:</h4>
<div style="border:1px solid black;padding:10px;">
<p>This is a paragraph. <span>This is a span element, inside the paragraph.</span></p>
</div>
</body>
</html>