<input type="radio" name="radiobutton" value="5" checked>5
<input type="radio" name="radiobutton" value="10" onchange="alert(this.previousSibling.previousSibling.value)">10
<input type="radio" name="radiobutton" value="15">15
<input type="radio" name="radiobutton" value="10" onchange="alert(this.previousSibling.previousSibling.value)">10
<input type="radio" name="radiobutton" value="15">15
<input type="radio" name="radiobutton" value="5" onclick="check(this)">5
<input type="radio" name="radiobutton" value="10" onclick="check(this)">10
<input type="radio" name="radiobutton" value="15" onclick="check(this)">15
<script language="javascript">
var temp=null;
function check(radio)
{
if(temp!=null)alert(temp);
temp=radio.value;
}
</script>