单选按钮只让用户从一系列选项中选择其中一个
<!DOCTYPE html>
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<html>
<head>
<title>TODO supply a title</title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body>
<div>TODO write content</div>
<form action="http://www.example.com/profile.php">
<p>选择其中一个:
<br />
<input type="radio" name="genre" value="rock" checked="checked" />第一个
<input type="radio" name="genre" value="pop" />第二个
<input type="radio" name="genre" value="jazz" />第三个
</p>
</form>
</body>
</html>