Dynamic Table With Add Row And Ajax Post

I have an stock listing html table. Adding rows or deleting rows with this javascript.

 <script>
function addRow(dataTable) {
"use strict";
var table = document.getElementById("dataTable");
var rowCount = table.rows.length;
if(rowCount < 20){
    var row = table.insertRow(rowCount);
    var colCount = table.rows[0].cells.length;
    for(var i=0; i<colCount; i++) {
        var newcell = row.insertCell(i);
        newcell.innerHTML = table.rows[0].cells[i].innerHTML;}  
}else{
     alert("En fazla 20 satır ekleyebilirsiniz.");
           
}
}

function deleteRow(dataTable) {
"use strict";
var table = document.getElementById("dataTable");
var rowCount = table.rows.length;
for(var i=0; i<rowCount; i++) {
    var row = table.rows[i];
    var chkbox = row.cells[0].childNodes[0];
    if(null !== chkbox && true === chkbox.checked) {
        if(rowCount <= 1) {
            alert("Tüm satırları silemezsiniz.");
            break;
        }
        table.deleteRow(i);
        rowCount--;
        i--;
    }
}
    }
  </script> 

And in each row i have select option which retrieves data from mysql database including stock ids.
When i select a stock from select option, getting price of from mysql table and showing in third td with ajax post.

  <script type="text/javascript">
  $(document).ready(function(){
  $("#tek_ice_stok_id").on('change',function(){
    var row = $(this).closest("tr");
    var tek_ice_stok_id = row.find(".tek_ice_stok_id").val();
    var tek_ice_birim_fiyat = row.find(".tek_ice_birim_fiyat").val();
    var dataString = "tek_ice_stok_id="+tek_ice_stok_id; 

  $.ajax({ 
    type: "POST", 
    url: "stok_fiyat_cek.php", 
    data: dataString, 
    success: function(result){ 
      row.find("td:eq(3)").html(result);
      
    }
  });
});
  })();
</script>

My first problem is when i add rows, the prices are all same in each rows price area. So i should do something and when i select 2nd or 3rd,etc select optons ajax should bring me those stocks prices.

Can anyone help me about this?

Thanks.

Searched for it many times but couldnt find exactly same.