ช่วยด้วยครับ ติด Warning PHP

มันขึ้นว่า Warning: Undefined array key "id_account" in D:\xampp\htdocs\project\src\chang.php on line 3 ครับคือผมต้องแก้ตรงไหนครับ 
นั่งแก้มาหลายชั่วโมงแล้วครับ แทบจะร้องไห้ หัวร้อน ด้วยครับ วอนผู้รู้ ช่วยผมที
<?php
require('dbconnect.php');
$id_account = $_GET['id_account'];
$sql = "SELECT * FROM account WHERE id_account = '$id_account'";
$result = mysqli_query($con, $sql);
$row = mysqli_fetch_assoc($result);
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>แก้ไขข้อมูลสมาชิก</title>
    <link href="./output.css" rel="stylesheet">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.2/css/all.min.css"
        integrity="sha512-SnH5WK+bZxgPHs44uWIX+LLJAJ9/2PkPKZ5QiAj6Ta86w+fsb2TkcmfRyVX3pBnMFcV7oQPJkl9QevSCWr3W6A=="
        crossorigin="anonymous" referrerpolicy="no-referrer" />
    <style>
        .btn-animate {
            transition: all 0.3s ease-in-out;
        }
        .btn-animate:hover {
            transform: translateY(-2px);
        }
        .btn-animate:active {
            transform: translateY(0);
            box-shadow: none;
        }
    </style>
</head>
<body>
    <div class=" bg-cover h-screen bg-center " style="background-image: url('/images/bg.png'); ">
        <div class="flex h-screen">
            <!-- Sidebar -->
            <div class="w-1/5 bg-gray-800 text-white p-4 flex flex-col ">
                <ul class="flex-grow">
                    <li class="mt-8">
                        <a href="main.html" class="btn-animate flex text-white-300 hover:text-red-500">
                            <span class="text-4xl font-bold">หน้าหลัก</span>
                        </a>
                    </li>
                    <li class="my-6">
                        <a href="changeprofile.html"
                            class="btn-animate flex items-center text-white-300 hover:text-red-500">
                            <img src="/images/address-card-regular (1).svg" alt="icon" class="w-7 h-7 mr-4 ">
                            <span>แก้ไขข้อมูลสมาชิก</span>
                        </a>
                    </li>
                    <li class="my-5">
                        <a href="history-page1.html"
                            class="btn-animate flex items-center text-white-300 hover:text-red-500">
                            <img src="/images/clock-regular (1).svg" alt="icon" class="w-7 h-7 mr-4  ">
                            <span>ประวัติการยืม-คืนทั้งหมด</span>
                        </a>
                    </li>
                </ul>
                <ul class="mt-auto">
                    <li>
                        <a href="Login.html" class="btn-animate flex items-center text-white-300 hover:text-red-500 ">
                            <img src="/images/power-off-solid (1).svg" alt="icon" class="w-7 h-7 mr-4 ">
                            <span>ออกจากระบบ</span>
                        </a>
                    </li>
                </ul>
            </div>
            <!-- Main content -->
            <div class="w-3/4 p-10 bg-cover bg-center" style="background-image: url('/mnt/data/image.png');">
                <div class="bg-white shadow-md p-4 mb-3">
                    <h1 class="text-2xl font-bold">แก้ไขข้อมูลสมาชิก</h1>
                </div>
                <div class="max-w-md mx-auto bg-white p-8 rounded-lg shadow-md">
                    <div class="mb-4 text-center">
                        <img class="w-28 h-28 rounded-full mx-auto" src="https://via.placeholder.com/150"
                            alt="Profile Picture">
                        <button
                            class="mt-5 px-4 py-2 text-white rounded-full bg-gradient-to-r from-sky-400 to-blue-500 hover:from-sky-600 hover:to-blue-700 btn-animate">อัปโหลดใหม่</button>
                    </div>
                    <form id="#">
                        <div class="mb-4">
                            <label class="block text-gray-700 text-sm font-bold mb-2" for="name">
                                ชื่อ-นามสกุล
                            </label>
                            <input
                                class="btn-animate shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline focus:ring-2 focus:ring-sky-300"
                                id="name" type="text" placeholder="ชื่อ-นามสกุล">
                        </div>
                        <div class="mb-4">
                            <label class="block text-gray-700 text-sm font-bold mb-2" for="class">
                                ชั้นปี
                            </label>
                            <input
                                class="btn-animate shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline focus:ring-2 focus:ring-sky-300"
                                id="class" type="text" placeholder="ชั้นปี">
                        </div>
                        <div class="mb-4">
                            <label class="block text-gray-700 text-sm font-bold mb-2" for="studentId">
                                รหัสประจำตัวนักศึกษา
                            </label>
                            <input
                                class="btn-animate shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline focus:ring-2 focus:ring-sky-300"
                                id="studentId" type="text" placeholder="รหัสประจำตัวนักศึกษา">
                        </div>
                        <a href="main.html">
                            <div class="flex items-center justify-between">
                                <img src="/images/save.svg" alt="icon" class="w-7 h-7 mr-2 ">
                                <button
                                    class="bg-gradient-to-r from-sky-400 to-blue-500 hover:from-sky-600 hover:to-blue-700 text-white font-bold py-2 px-4 rounded focus:outline-none focus:shadow-outline btn-animate"
                                    type="button" onclick="submitForm()">
                                    บันทึก
                                </button>
                            </div>
                        </a>
                    </form>
                </div>
            </div>
        </div>
    </div>
</body>
</html>
แสดงความคิดเห็น
โปรดศึกษาและยอมรับนโยบายข้อมูลส่วนบุคคลก่อนเริ่มใช้งาน อ่านเพิ่มเติมได้ที่นี่