ต้องการคำนวนค่าส่งและยอดรวมด้วย jQuery แบบไม่ต้องรีเฟรชหน้าจอครับ

Sum Total: <span id='total'>2,750.20</span> บาท
<legend>
<div>
<input type='radio' name='transferfee' value='40' />ลงทะเบียน 40
</div>
<div>
<input type='radio' name='transferfee' value='60' />EMS 60
</div>

</legend>

<div>
ยอดรวมทั้งสิ้น : <span id='nettotal'></span> บาท
</div>

<script  src="https://code.jquery.com/jquery-2.2.4.min.js"  integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44="	  crossorigin="anonymous"></script>
<script>
$("input[name='transferfee']").click(function(){
	var current = $(this),
  		total = $("#total").text().replace(",",""),
      net = 0;
      net = parseFloat(total) + parseFloat(current.val());

     $("#nettotal").text(net.toString().replace(/\B(?=(?:\d{3})+(?!\d))/g, ','));
});
</script>

<?php session_start();?>
Sum Total: <span id='total'>2,750.20</span> บาท
<legend>
<div>
<input type='radio' name='transferfee' value='40' />ลงทะเบียน 40
</div>
<div>
<input type='radio' name='transferfee' value='60' />EMS 60
</div>

</legend>

<div>
ยอดรวมทั้งสิ้น : <span id='nettotal'></span> บาท
</div>

<script  src="https://code.jquery.com/jquery-2.2.4.min.js"  integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44="	  crossorigin="anonymous"></script>
<script>
$("input[name='transferfee']").click(function(){
	var current = $(this),
  		total = $("#total").text().replace(",",""),
      net = 0;
      net = parseFloat(total) + parseFloat(current.val());

     $("#nettotal").text(net.toString().replace(/\B(?=(?:\d{3})+(?!\d))/g, ','));
     $.post("create_session.php",{varname:'netTotal',value:net} , function(data){
          alert(data);
     });
});
</script>

<?php
session_start();
if(isset($_POST["varname"] ,$_POST["value"]))}
      $_SESSION["{$_POST["varname"]}"][session_id()]  = $_POST["value"];
      echo "Now the Total amount is: ",number_format($_POST["value"],2)," Baht";
}else{
      echo "You cheated on me!";
}
?>