[Sweet]

Для radio можно, например, так:

<input type="radio" name="browser" value="ie" onClick="f(this)"> Internet Explorer<Br>
<input type="radio" name="browser" value="opera" onClick="f(this)"> Opera<Br>
<input type="radio" name="browser" value="firefox" onClick="f(this)"> Firefox<Br>

<script>
function f(el){
  if(arguments.callee.value != el.value){
    arguments.callee.value = el.value
    alert(el.value);
  }
}
</script>