<script type='text/javascript' src='//code.jquery.com/jquery-1.9.1.js'></script>
<link rel="stylesheet" type="text/css" href="/css/result-light.css">
<style type='text/css'></style>

<script type='text/javascript'>

$(document).ready(function() {
    $("#numList").append("<option value=''>번호 선택</option>");
    $('#ban').change(function(){
        // alert($('#ban option:selected').val());
        // alert($(this).val());
        // alert($(this).children('option:selected').text());

         var bc = "";
         var i1 = "";
         var bv = $("#ban").val();

      $("#numList option").each(function() {
          $(this).remove();
      });
  

         if(bv == "A반"){
            bc = 8;
             $("#numList").append("<option value=''>A반 번호 선택</option>");
             for(var i=0; i<bc; i++){
                 i1 = i + 1;
             // $("#numList option").each(function(){
                 $("#numList").append("<option value='A_"+i1+"반'>A_"+i1+"반</option>");
        // }); 
            }
         }else if(bv == "B반"){
             bc = 12;
             $("#numList").append("<option value=''>B반 번호 선택</option>");
             for(var i=0; i<bc; i++){
                 i1 = i + 1;
                 $("#numList").append("<option value='B_"+i1+"반'>B_"+i1+"반</option>");
             }
         }else if(bv == "C반"){
             bc = 9;
             $("#numList").append("<option value=''>C반 번호 선택</option>");
             for(var i=0; i<bc; i++){
                 i1 = i + 1;
                 $("#numList").append("<option value='C_"+i1+"반'>C_"+i1+"반</option>");
             }
       }else{
             $("#numList").append("<option value=''>번호 선택</option>");
         }

});
 // $("#ban option:selected").text();

});

function selectNum(){
    $.ajax({type:"POST",
            url:"",
            dataType:"json",
            success:function(){
                alert($("#ban").val() + " / " + $("#numList").val());
            }
    });

}

</script>


<body>

<form name="form" method="post">

<select name="ban" id="ban" onchange="selectBan(this.value)">
    <option value = "0">반 선택</option>
    <option value = "A반">A반</option>
    <option value = "B반">B반</option>
    <option value = "C반">C반</option>
</select>

    <select name="numList" id="numList" onchange="selectNum(this.value)"></select>

    </form>

</body>

 

 

실행 : http://jsfiddle.net/drrp2xox/6/