jQuery GET overwiting POST - php

Question

I've got a simple jQuery script that isn't behaving correctly. What am I doing wrong? The idea is that the user enters a value into a textbox and then clicks a button. The jQuery then uses POST to send the value to a PHP file. The PHP file then runs a simple SQL query and gives a response. jQuery .load is then used to refresh the div containing the original php.
Using Chrome's tools, I've noticed that the response for POST is perfect. However, it then gets overwritten by a GET with no data.
jQuery:
$("#GOtest").click(function() {
var customer = $("#customer").val();
if (customer == '') {
$('#alert_formula_save_failed').show();
}
else {
$.post("../assets/forms/formulations/set_session.php", {
customer: customer,
}, function(data) {
$('#alert_formula_save_success').show();
$('#dynamic').load('../assets/forms/formulations/set_session.php');
$('#alert_formula_save_failed').hide();
setTimeout(function() { $('#alert_formula_save_success').fadeOut('fast'); }, 3000);
});
}
});
PHP:
<?php
$customer = null;
$customer = 'Test' ;
$customer2 = $_POST['customer'] ;
.. db connection bits ;
try
{
$PDO = new PDO( "mysql:host=".$host.";"."dbname=".$dbname, $user, $pass);
}
catch(PDOException $e)
{
die($e->getMessage());
}
$PDO->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "SELECT * FROM db_customers where customer = '$customer' ";
$stmt = $PDO->prepare($sql);
$stmt->execute(array($id));
$data = $stmt->fetch(PDO::FETCH_ASSOC);
$PDO = null;
$iscurrent = $data['iscurrent'];
echo '<br>' ;
echo 'Response 1-' ;
echo $iscurrent;
echo '<br>' ;
echo 'Response 2-' ;
echo $customer2 ;
?>
HTML:
<form id="testform" name="testform" method="POST">
<button type="button" name="GOtest" id="GOtest" class="btn btn-info">
<i class="fa fa-frown-o"></i>
SET SESSION
</button>
The idea being that 'response 1' just echoes a predefined value. Response 2 should just echo out whatever is typed into the text input box.. but the GET overwrites everything.

Answer 1

The "issue" is this line:
$('#dynamic').load('../assets/forms/formulations/set_session.php');
It uses GET by default.
Try using this in its place:
$('#dynamic').html(data);