How can I validate an expiry date in Javascript?

I’m a beginner to HTML, Javascript, and coding in general. For an assessment, I’m required to create a form with HTML, and validate it with a Javascript file. If an inputted answer isn’t valid, it should return false. For a credit card, a user is required to input an expiry date, and if the date has already passed, it should return false. Though despite this, no matter how much I troubleshoot, it always returns true with no errors. Any help would be appreciated!

HTML

<form name="userForm" onsubmit="return validateForm()">
        <fieldset>
            <legend>Payment details</legend>
                <div>
                    <lable for="exMonth">Expiry MM/YY</lable>
                    <select id="exMonth" name="exMonth">

                        <option value="01">01</option>
                        <option value="02">02</option>
                        <option value="03">03</option>
                        <option value="04">04</option>
                        <option value="05">05</option>
                        <option value="06">06</option>
                        <option value="07">07</option>
                        <option value="08">08</option>
                        <option value="09">09</option>
                        <option value="10">10</option>
                        <option value="11">11</option>
                        <option value="12">12</option>

                    </select>
                    <select id="exYear" name="exYear">

                        <option value="2024">2024</option>
                        <option value="2025">2025</option>
                        <option value="2026">2026</option>
                        <option value="2027">2027</option>
                        <option value="2028">2028</option>

                    </select>
                </div>
        </fieldset>
    
        <br>

        <input type="submit">
        <button>Help</button>

        <p id="demo"></p>
        <script src="../js/assessment1.js">
        </script>

Javascript

    function validateForm()
{
    var exMonth=document.getElementById("exMonth");
    var exYear=document.getElementById("exYear");
    var date = new Date ();
    var month = date.getMonth();
    var year = date.getFullYear();

    if (year> exYear || (year === exYear && month >= exMonth))
        {
            alert("Your expirey date has passed");
            return false;
        }
    alert("Thanks");
    return true;
}

I’ve honestly been troubleshooting so much I’ve lost what I’ve already tried. I’ll take any advice that can be provided 🙂