我正在制作这个产品页面。基本上，它按ID显示产品，并为您提供将其添加到购物车的选项。我的问题是，每次刷新页面时，存储在$_SESSION中的数据都会丢失。
<?php
include 'scripts'init.php'; // contains session_start(); and the functions
if(!IsProductIdSafeAndExisting())
{
session_write_close();
header("Location: shop.php");
die();
}
if(isset($_POST['quantity'])) // adds current item to cart but gets lost after refresh
AddItemToCart($_GET["id"],$_POST['quantity']);
$id = $_GET["id"];
$name = GetProductField($id,"name");
$image = GetProductField($id,"image");
$price = GetProductField($id,"price");
$stock = GetProductField($id,"stock");
$details = GetProductField($id,"details");
$total_products = GetTotalProducts();
$total_price = GetTotalProductsPrice();
LoadHeaderByTitle($name." | Magazin Vinuri");
?>
<body>
<div id="page">
<?php LoadNavigationBy(""); ?>
<div id="body">
<div class="header">
<div>
<h1><?php echo $name; ?></h1>
</div>
</div>
<div class="singlepost">
<div class="featured">
<img src="images/<?php echo $image; ?>" alt="">
<h1><?php echo $name.' - '.$price.' lei'; ?></h1>
<span>Mai sunt <?php echo '<strong>'.$stock.'</strong>'; ?> bucati ramase.</span>
<p><?php echo $details; ?></p>
<div class="additem">
<center>
<form method="POST" action="product.php?id=<?php echo $id; ?>">
<input type="text" name="quantity" value="Cantitate" onblur="this.value=!this.value?'Cantitate':this.value;" onfocus="this.select()" onclick="this.value='';">
<input type="submit" value="Adauga" id="submit">
</form>
</center>
</div>
</div>
<div class="sidebar">
<h1>Cosul tau</h1>
<img src="images/cart.png" alt="">
<h2><?php echo $total_price; ?> lei</h2><br>
<p>Momentan aveti <strong><?php echo $total_products; ?></strong> produse in cos. Pentru a edita lista de produse dati click pe butonul de mai jos.</p>
<a href="cart.php" class="more">vezi cumparaturi</a>
</div>
</div>
</div>
<?php include 'scripts'overall'foot.php' ?>
init.php
<?php
session_start();
require 'database'connect.php';
require 'functions'general.php';
require 'functions'engine.php';
?>
问题是我像这样存储产品id $_SESSION[10]=什么;这是错误的，因为它与$_SESSION['10']=某事相同;所以我把它改成$_SESSION['id_10']=something;现在可以运行了