刚刚开始接触sql和php，并试图建立一个简单的用户帐户系统-一个忘记密码的电子邮件链接。
我下面有一个脚本，我试图用它来更新用户的密码。他们收到一封带有链接的电子邮件。链接如下所示： http://localhost:8887/email-password-reset.php?id=1 .
我知道这是不安全的，很容易破解！我计划使用随机生成的数字串，一旦我得到这个工作！
我正在尝试使用 $_GET 函数来获取 id . 但是我不相信 $_GET["id"] 正在被传递到 $param_id 变量。
我是新来的，所以不知道如何纠正它！
如何将参数id设置为 $_GET 价值？
至少我认为问题出在控制台的错误上( Undefined variable: param_id!) 提前谢谢！

<?php
//session_start();
require_once "config.php";

// Define variables and initialize with empty values
$new_password = $confirm_password = "";
$new_password_err = $confirm_password_err = "";
$param_id = ''; 

// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){

    // Validate new password
    if(empty(trim($_POST["new_password"]))){
        $new_password_err = "Please enter the new password.";
    } elseif(strlen(trim($_POST["new_password"])) < 6){
        $new_password_err = "Password must have atleast 6 characters.";
    } else{
        $new_password = trim($_POST["new_password"]);
    }

    // Validate confirm password
    if(empty(trim($_POST["confirm_password"]))){
        $confirm_password_err = "Please confirm the password.";
    } else{
        $confirm_password = trim($_POST["confirm_password"]);
        if(empty($new_password_err) && ($new_password != $confirm_password)){
            $confirm_password_err = "Password did not match.";
        }
    }

    // Check input errors before updating the database
    if(empty($new_password_err) && empty($confirm_password_err)){
        // Prepare an update statement
        $sql = "UPDATE users SET password = ? WHERE id = ?";

        if($stmt = mysqli_prepare($link, $sql)){
            // Bind variables to the prepared statement as parameters
            mysqli_stmt_bind_param($stmt, "si", $param_password, $param_id);

            // Set parameters
            $param_password = password_hash($new_password, PASSWORD_DEFAULT);
            $param_id = (isset($_GET['id']) ? $_GET['id'] : '');

            // Attempt to execute the prepared statement
            if(mysqli_stmt_execute($stmt)){
                // Password updated successfully. Destroy the session, and redirect to login page
                session_destroy();
                header("location: login.php");
                exit();
            } else{
                echo "Oops! Something went wrong. Please try again later.";
            }
        }

        // Close statement
        mysqli_stmt_close($stmt);
    }

    // Close connection
    mysqli_close($link);
}
?>