Sent data using Jquery Ajax to another page not working

Question

I sent some data using ajax from test.php to another page order.php, but when i navigate to order.php and try to echo the data, I get the " Undefined index..." error message.

I have done console.log in the text.php file and confirmed that the data values were successfully set. But it doesn't reflect on the order.php file. I also started session in both files.

NOTE: Before i can send ajax data to DB, I will need to get the data via $_POST['data'] in order.php and save in a variable so that i can proceed to insert the values in the DB. In this case, I CAN'T even get the data. For some reason, the data posted to order.php did not get to the file. That's the issue I want to resolve. How can I get my ajax post data to order.php so that i can use it for something else?

Please what could be wrong with my code? See Code Below:

test.php

<script type="text/javascript">
            $(document).ready(function(){
                $(".addItemBtn").click(function(event){
                    var $form = $(this).closest(".formclass");
                    var qty = $form.find(".naira-input").val(); //form input`
                    var total = $('.amount').html(); //from javascript innerhtml

                    
                $.ajax({
                     url:'order.php',
                     method:'post',
                     data:{grandTotal:total, nairaRate:qty}, // dont worry about this. The values are succesfully set in console.log
                     success:function(response)
                     {
                          console.log(response+' values were sent successfully');// I tested and confirmed that data was sent successfully
                    }
                     
                });
            });
        });


        </script>

order.php

    <?php
    session_start();
    
 $_SESSION['grandTotal']= $_POST['grandTotal'];
      $_SESSION['nairaRate']=$_POST['nairaRate'];

    echo $_SESSION['grandTotal']; // I get Undefined index error here
    echo  $_SESSION['nairaRate']; // I get Undefined index error here
    
    ?>

Answer 1

When you navigate to order.php the code which assigns values to the session runs again , only thing time you haven't made a post request so the values aren't set.

Don't use the same endpoint for displaying the data as you do for setting it.