在线运行代码 - 菜鸟教程

<!DOCTYPE html>
<html>
<head>
<script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js">
</script>
<script>
$(document).ready(function(){
  $("p:last").css("background-color","yellow");
});
</script>
</head>
<body>

<p>This is the first paragraph.</p>
<p>This is the second paragraph.</p>
<p>This is the last paragraph.</p>

</body>
</html>

源代码

动行结果