<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
</head>
<body>
<form>
<div>
<input type="radio" value="a" data-checked='true'>aaa
<input type="radio" value="b">bbb
<input type="radio" value="c" checked>ccc
<input type="radio" value="d" checked data-checked='false'>ddd
</div>
<div>
<input type="checkbox" value="A" data-checked='true'>AAA
<input type="checkbox" value="B">BBB
<input type="checkbox" value="C" checked>CCC
<input type="checkbox" value="D" checked data-checked='false'>DDD
<input type="checkbo