focus-blur.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="js/scripts/jquery.js"></script>
    <style>
        .change{
            outline: none;
            border: 1px solid red;
            background-color:#fcc;
        }
        .container{
            width: 400px;
            margin: 20px auto;
        }
        .container div{
            margin: 20px;
        }
    </style>
    <script>
        $(function(){
            $('input').focus(function(){
                $(this).addClass('change')
            }).blur(function(){
                $(this).removeClass('change')
            })
        })
    </script>
</head>
<body>
    <form class="container">
        <fieldset>
            <legend>文本框获取焦点和失去焦点</legend>
            <div>
                <label for="username">名称：</label>
                <input type="text" id="username">
            </div>
            <div>
                <label for="password">密码：</label>
                <input type="password" id="password">
            </div>
            <div>
                <label for="msg">详细信息：</label>
                <textarea id="msg"></textarea>
            </div>
        </fieldset>
    </form>
</body>
</html>