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);
        }
      });
    }
  });
  

// html code

  
  

    

    

		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'];
        // ...
?>
      

        

          

            
            

              

              
  /-

            
            

              

                

                  

                    Quantity : 
                  
                  

                    
                  
                
                
                
                
                
                
                  Add to
                  cart