菜鸟教程在线编辑器

AI 编程工具
 
                <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title>
<script src="https://cdn.staticfile.net/jquery/1.10.2/jquery.min.js">
</script>
<script>
$(document).ready(function(){
  $(":selected").css("background-color","red");
});
</script>
</head>
<body>

<form action="">
用户名: <input type="text" name="user"><br>
汽车品牌:
<select>
  <option>Volvo</option>
  <option selected="selected">Saab</option>
  <option>Mercedes</option>
  <option>Audi</option>
</select>
</form>

</body>
</html>
              