[JaVaScRiPt] radio 사용

 <script type="text/javascript">
  function checkForm(){

   var local = document.getElementsByName("localeSel");
   var localCheck = false;
   
   for(i=0 ; i <= local.length -1 ; i++){
    if(local[i].checked == true){
     alert(local[i].value + "선택");
     localCheck = true;
    }
   }
   
   if(localCheck == false){
    alert("선택 항목이 누락 되었습니다.");
    return;
   }
  }
 </script>



  <input type="radio" name="localeSel" id="localeSel" value="1">1선택<br>
  <input type="radio" name="localeSel" id="localeSel" value="2">2선택<br>
  <input type="radio" name="localeSel" id="localeSel" value="3">3선택<br>
  
  <input type="button" value="입력완료" onClick = "javascript:checkForm()">