ช่วยแนะนำตัวอย่างในการรวมค่าใน textfield ด้วยครับ กรณีมีการเพิ่ม field ขึ้นมาใหม่

var sumtotal=0;

$("#prototal_"+intLine+"").change(function(){
    sumtotal = sumtotal+parseInt($(this).val());
});

$("#your_summary_field").val(sumtotal); //เปลี่ยนชื่อช่องรวมเอาเองน่ะครับ

function CreateNewRow()
	{
		var intLine = parseInt(document.frmMain.hdnMaxLine.value);
		intLine++;
			
		var theTable = document.all.tbExp
		var newRow = theTable.insertRow(theTable.rows.length)
		newRow.id = newRow.uniqueID
		
		var item1 = 1
		var newCell
		
		//*** Column 1 ***//
		newCell = newRow.insertCell(0)
		newCell.id = newCell.uniqueID
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<select class=\"form-control\" NAME=\"prodname_"+intLine+"\" id=\"prodname_"+intLine+"\">\
				      		<option value=\"\">--- กรุณาเลือก ---</option>\
				      		<?php $post_data1 = $data->tran_pageprodname();
	  						foreach ($post_data1 as $post1) {
						    echo "<option value= '".$post1["Prod_desc"]."'>".$post1["Prod_desc"]."</option>";
							}?></select>"

		//*** Column 2 ***//
		newCell = newRow.insertCell(1)
		newCell.id = newCell.uniqueID
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<select class=\"form-control\" NAME=\"prodtype_"+intLine+"\" id=\"prodtype_"+intLine+"\">\
				      		<option value=\"\">--- กรุณาเลือก ---</option>\
				      		<?php $post_data1 = $data->tran_pagetypename();
	  						foreach ($post_data1 as $post1) {
						    echo "<option value=".$post1["Prod_type_id"].">".$post1["Prod_type_desc"]."</option>";
						     } ?></select>";		
		
		//*** Column 3 ***//
		newCell = newRow.insertCell(2)
		newCell.id = newCell.uniqueID
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<input type=\"number\" class=\"form-control\" NAME=\"proprice_"+intLine+"\" id=\"proprice_"+intLine+"\">";


		newCell = newRow.insertCell(3)
		newCell.id = newCell.uniqueID
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<input type=\"number\" class=\"form-control\" NAME=\"proqty_"+intLine+"\" id=\"proqty_"+intLine+"\">";	

		newCell = newRow.insertCell(4)
		newCell.id = newCell.uniqueID
		newCell.setAttribute("className", "css-name");
		newCell.innerHTML = "<input type=\"number\" class=\"form-control\" NAME=\"prototal_"+intLine+"\" id=\"prototal_"+intLine+"\">";

		$(document).ready(function() {
	      	$("#prodtype_"+intLine+"").change(function() {
	          	var name = $("#prodname_"+intLine+"").val();
	          	var type = $("#prodtype_"+intLine+"").val();
	          	var jsonObj = {"prodname": name, "prodtype": type}
	          	$.ajax({
	             	type: "POST",
	            	url: "./lib/getform2.php",
	             	data: jsonObj,
	             	success: function(result) {
	            	//alert(result);
	            	$("#proprice_"+intLine+"").val(result);
	            	//alert($('#txtval').val());
	             	}
	           });
	      	});
	      	$("#proqty_"+intLine+"").change(function() {
	          	var qty = $("#proqty_"+intLine+"").val();
	          	var prodprice = $("#proprice_"+intLine+"").val();
	          	var total = prodprice*qty;
	          	$("#prototal_"+intLine+"").val(total);
	      	});
	      	
	      	var sumtotal=0;
			$("#prototal_"+intLine+"").change(function(){
			    sumtotal = sumtotal+parseInt($(this).val());
			});
			$("#ordertotal").val(sumtotal);
    	});		
			
		document.frmMain.hdnMaxLine.value = intLine;
	}

var sumtotal=0;

$("#prototal_"+intLine+"").change(function(){
    //var obj= $(this);
    $("#prototal_"+intLine+"").each(function(index,val){
      sumtotal = sumtotal+parseInt(val);
    });
    
});

$("#your_summary_field").val(sumtotal); //เปลี่ยนชื่อช่องรวมเอาเองน่ะครับ