Duplication of items in the cart

Hi Team

I am having an issue on my cart its duplicating values on the cart. Meaning if i add 1 item at a time it doubles that value to the cart. How do i fix this issue?

// jquery code

$(document).ready(function() {

    // Send product details in the server
    $(".addItemBtn").click(function(e) {
      e.preventDefault();
      var $form = $(this).closest(".form-submit");
      var pid = $form.find(".pid").val();
      var pname = $form.find(".pname").val();
      var pprice = $form.find(".pprice").val();
      var pimage = $form.find(".pimage").val();
      var pcode = $form.find(".pcode").val();

      var pqty = $form.find(".pqty").val();
	  var pqty = 1;

      $.ajax({
        url: 'action.php',
        method: 'post',
        data: {
          pid: pid,
          pname: pname,
          pprice: pprice,
          pqty: pqty,
          pimage: pimage,
          pcode: pcode
        },
        success: function(response) {
          $("#message").html(response);
          window.scrollTo(0, 0);
          load_cart_item_number();
        }
      });
    });

    // Load total no.of items added in the cart and display in the navbar
    load_cart_item_number();

    function load_cart_item_number() {
      $.ajax({
        url: 'action.php',
        method: 'get',
        data: {
          cartItem: "cart_item"
        },
        success: function(response) {
          $("#cart-item").html(response);
        }
      });
    }
  });
  </script>

// html code

  <!-- Displaying Products Start -->
  <div class="container">
    <div id="message"></div>
    <div class="row mt-2 pb-3">
		<?php
    include 'dbconn.php';
    $stmt = $conn->prepare('SELECT * FROM products');
    $stmt->execute();
    $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
    foreach ($rows as $row):
        // Access the data using $row['column_name']
        $productID = $row['id'];
        $productName = $row['product_name'];
        // ...
?>
      <div class="col-sm-6 col-md-4 col-lg-3 mb-2">
        <div class="card-deck">
          <div class="card p-2 border-secondary mb-2">
            <img src="<?= $row['product_image'] ?>" class="card-img-top" height="250">
            <div class="card-body p-1">
              <h4 class="card-title text-center text-info"><?= $row['product_name'] ?></h4>
              <h5 class="card-text text-center text-danger"><i class="fas fa-zar-sign"></i>&nbsp;&nbsp;<?= number_format($row['product_price'],2) ?>/-</h5>

            </div>
            <div class="card-footer p-1">
              <form action="" class="form-submit">
                <div class="row p-2">
                  <div class="col-md-6 py-1 pl-4">
                    <b>Quantity : </b>
                  </div>
                  <div class="col-md-6">
                    <input type="number" class="form-control pqty" value="<?= $row['product_qty'] ?>">
                  </div>
                </div>
                <input type="hidden" class="pid" value="<?= $row['id'] ?>">
                <input type="hidden" class="pname" value="<?= $row['product_name'] ?>">
                <input type="hidden" class="pprice" value="<?= $row['product_price'] ?>">
                <input type="hidden" class="pimage" value="<?= $row['product_image'] ?>">
                <input type="hidden" class="pcode" value="<?= $row['product_code'] ?>">
                <button class="btn btn-info btn-block addItemBtn"><i class="fas fa-cart-plus"></i>&nbsp;&nbsp;Add to
                  cart</button>
              </form>
            </div>
          </div>
        </div>
      </div>
      <?php endforeach; ?>
    </div>
  </div>
  <!-- Displaying Products End -->