yige.org 试一个

<!DOCTYPE html>
<html>
<head>
<style> 
input:checked
{
background:#ff0000;
}
</style>
</head>
<body>

<form action="">
<input type="radio" checked="checked" value="male" name="gender" /> Male<br>
<input type="radio" value="female" name="gender" /> Female<br>
<input type="checkbox" checked="checked" value="Bike" /> I have a bike<br>
<input type="checkbox" value="Car" /> I have a car 
</form>

<p><b>注释：</b>本例只在 Opera 中正确地工作！</p>

</body>
</html>

结果:

编辑上面的代码，点击查看结果。

yige.org - 试一个