<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>radio默认选中第一个</title>
<link rel="stylesheet" type="text/css" href="style/style.css" media="all" />
</head>
<body>
<label for=""><input type="radio" value="" name="a"/></label>
<label for=""><input type="radio" value="" name="a"/></label>
<script type="text/javascript">
var rm=document.getElementsByName("a")
var flag=false;
for(var i=0;i<rm.length;i++){
if(rm[i].checked){
flag=false;
break;
}
}
if(!flag){
rm[0].checked=true;
}
</script>
</body>
</html>