关于radio默认选中
<html>
<head>
<title>My Page</title>
</head>
<body>
<form name="myform" action="http://www.mydomain.com/myformhandler.cgi" method="POST">
<div align="center"><br>
<input type="radio" name="group1" value="Milk"> Milk<br>
<input type="radio" name="group1" value="Butter" checked> Butter<br>
<input type="radio" name="group1" value="Cheese"> Cheese
<hr>
<input type="radio" name="group2" value="Water"> Water<br>
<input type="radio" name="group2" value="Beer"> Beer<br>
<input type="radio" name="group2" value="Wine" checked> Wine<br>
</div>
</form>
</body>
</html>