所属分类：web前端开发
您可以尝试运行以下代码来实现 :focus 伪类
现场演示
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<html>
<head>
<style>
input:focus {
background-color: orange;
}
</style>
</head>
<body>
<form action = "">
Subject <input type = "text" name = "subject"><br>
Student: <input type = "text" name = "student"><br>
Age: <input type = "number" name = "age"><br>
<input type = "submit" value = "Submit">
</form>
</body>
</html>
