W3School TIY
编辑您的代码：
<!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>
查看结果: