在线运行代码 - 菜鸟教程

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

<form action="">
用户名: <input type="text" name="user"><br>
密码: <input type="password" name="password"><br>
兼容性: <input type="image" src="https://www.cainiaoplay.com/images/compatible_ie.gif" width="31" height="30">
</form>

</body>
</html>
源代码

动行结果
