Update Stock Input Value for each Same Item Selected

[Ronnel_Dela_Cruz]

I have a problem, I need to update the stock value (real-time) for each select box that has the same Item, for example on the image attached, there are two select input that has the same item.

I want the stock quantity on the second row to be updated depending on the difference of stock quantity and quantity input.

Example:

1st Row: QTY: 3000 , STOCK : 6000
2nd Row: QTY: 5000 , STOCK : 3000 (3000 because on the 1st row the stock has been deducted by 3000)

Hope you can help. Here’s my code below, Thank you

$('select[name="selector[]"]').change(function () {
$.ajax({
url: 'changeitem',
context: this,
dataType: 'json',
data: {
'itemid': this.value
},
success: function(info) {
var soid = $('#soid').val();
$(this).closest('td').next().next().find("#xstock").val(info.stock);
$.ajax({
url: 'getsoitemqty',
context: this,
dataType: 'json',
data: {
'itemid': this.value,
'soid': soid
},
success: function(info) { 
$(this).closest('td').next().find("#xqty").val(info.qty);
var stock = 0;
var qty = 0;
var needed = 0;
stock =  $(this).closest('td').next().next().find("#xstock").val();
qty =   $(this).closest('td').next().find("#xqty").val();
needed = parseInt(qty) - parseInt(stock); 
if(needed<=0) {
needed  = 0;
}
$(this).closest('td').next().next().next().find("#xneedqty").val(needed);
}
});
}
});
});[