【radiobutton】
<html>
<body>
<script language="JavaScript">
function checkBox(){
if(document.form1.button1.defaultChecked == true){
console.log("Box1 is checked by default");
} else if(document.form1.button2.defaultChecked == true){
console.log("Box 2 is checked by default");
}
}
</script>
<form name="form1">
<input type="radio" name=button1>Box 1
<br>
<input type="radio" name=button2 CHECKED>Box 2
<br><br>
<input type="button" value="Get Default" onClick='checkBox()'>
</form>
</body>
</html>
