ถามพี่ๆเรื่อง การใช้ ajax auto fill ร่วมกับ ปุ่มเพิ่ม text box ค่ะ

newCell.setAttribute("OnChange", "doCallAjax('txtProductID3','txtProductName3','txtPrice3');");

newCell.innerHTML = "<center><INPUT TYPE=\"TEXT\" SIZE=\"5\" NAME=\"Column5_"+intLine+"\" VALUE=\"\" OnChange=\"JavaScript:doCallAjax('txtProductID3','txtProductName3','txtPrice3');\"></center>"  

<? $link = mysql_connect("localhost", "root", "password");            
        mysql_query("use project;");                                  
    	mysql_query("set NAMES tis620"); 
	$strsql = "select * from nutrients";
	$objquery = mysql_query($strsql); ?>
<script language="javascript">

function CreateSelectOption(ele)
{
var objSelect = document.getElementById(ele);
var Item = new Option("", "");
objSelect.options[objSelect.length] = Item;
<?
while($objResult = mysql_fetch_array($objquery))
{
?>
var Item = new Option("<?=$objResult["NutrientName"];?>", "<?=$objResult["NutrientID"];?>");
objSelect.options[objSelect.length] = Item;
<?
}
?>
}
function CreateNewRow()
{
var intLine = parseInt(document.frmMain.hdnMaxLine.value);
intLine++;
var theTable = document.getElementById("tbExp");
var newRow = theTable.insertRow(theTable.rows.length)
newRow.id = newRow.uniqueID
var newCell
//*** Column 1 ***//
newCell = newRow.insertCell(0);
newCell.id = newCell.uniqueID;
newCell.setAttribute("className", "css-name");
newCell.innerHTML = "<center><SELECT NAME=\"txtnutr_"+intLine+"\" ID=\"txtnutr_"+intLine+"\ value=\"\" OnChange=\"JavaScript:doCallAjax('txtnutr_"+intLine+"','txtuni_"+intLine+"');\"></SELECT></center>";

//*** Create Option ***//
CreateSelectOption("txtnutr_"+intLine)

document.frmMain.hdnMaxLine.value = intLine;

//*** Column 2 ***//
newCell = newRow.insertCell(1);
newCell.id = newCell.uniqueID;
newCell.setAttribute("className", "css-name");
newCell.innerHTML = "<center><INPUT TYPE=\"TEXT\" SIZE=\"5\" NAME=\"txtvolu_"+intLine+"\" ID=\"txtvolu_"+intLine+"\"  VALUE=\"\"></center>";

//*** Column 3 ***//
newCell = newRow.insertCell(2);
newCell.id = newCell.uniqueID;
newCell.setAttribute("className", "css-name");
newCell.innerHTML = "<center><INPUT TYPE=\"TEXT\" SIZE=\"5\" NAME=\"txtuni_"+intLine+"\" ID=\"txtuni_"+intLine+"\"  VALUE=\"\"></center>";
}

function RemoveRow()
{
intLine = parseInt(document.frmMain.hdnMaxLine.value);
if(parseInt(intLine) > 0)
{
theTable = document.getElementById("tbExp"); 
theTableBody = theTable.tBodies[0];
theTableBody.deleteRow(intLine);
intLine--;
document.frmMain.hdnMaxLine.value = intLine;
} 
}  

var HttPRequest = false;

function doCallAjax(fNutrientID,fUnit) {
HttPRequest = false;
if (window.XMLHttpRequest) { // Mozilla, Safari,...
HttPRequest = new XMLHttpRequest();
if (HttPRequest.overrideMimeType) {
HttPRequest.overrideMimeType('text/html');
}
} else if (window.ActiveXObject) { // IE
try {
HttPRequest = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
HttPRequest = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}

if (!HttPRequest) {
alert('Cannot create XMLHTTP instance');
return false;
}

var url = 'AjaxGetFill.php';
var pmeters = "tNutrientID=" + encodeURI( document.getElementById(fNutrientID).value);

HttPRequest.open('POST',url,true);

HttPRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
HttPRequest.setRequestHeader("Content-length", pmeters.length);
HttPRequest.setRequestHeader("Connection", "close");
HttPRequest.send(pmeters);

HttPRequest.onreadystatechange = function()
{

//if(HttPRequest.readyState == 3)  // Loading Request
//{
//document.getElementById(fProductName).innerHTML = "..";
//}

if(HttPRequest.readyState == 4) // Return Request
{
var myProduct = HttPRequest.responseText;
if(myProduct != "")
{
var myArr = myProduct.split("|");
document.getElementById(fUnit).value = myArr[0];

}
}

}

}
</script>

newCell.innerHTML = "<center><SELECT NAME=\"txtnutr_"+intLine+"\" ID=\"txtnutr_"+intLine+"\ value=\"\" OnChange=\"JavaScript:doCallAjax('txtnutr_"+intLine+"','txtuni_"+intLine+"');\"></SELECT></center>";

newCell.innerHTML = "<center><SELECT NAME=\"txtnutr_"+intLine+"\" ID=\"txtnutr_"+intLine+"\" value=\"\" OnChange=\"JavaScript:doCallAjax('txtnutr_"+intLine+"','txtuni_"+intLine+"');\"></SELECT></center>";