[Dilettante_Pro]

<input type="radio" name="serve" value="1" checked>
<input type="radio" name="serve" value="2">
<script>
var inpServe = document.querySelectorAll('[name="serve"]');

for(var i = 0; i < inpServe.length; i++) {
   inpServe[i].onclick = function() {
       var o=document.querySelector('[name="serve"]:checked');
       alert(o.value);
}};
</script>