Проверка пароля JavaScript onkeydown не работает

"user strict";
window.onload = init;
function init() {
    document.getElementById("newPassword").onkeydown = checkPassword;
    document.getElementById("confirmPassword").onkeydown = checkConfirm;
}
function checkPassword(event){
    let newPass = document.getElementById("newPassword").value;
    var passwordRegex = new RegExp("^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*&])[A-Za-z\d]@$!%*?&]{8,}$")
    if (!passwordRegex.test(newPass)){
        feedback.innerHTML = "'"+newPass + "' is not secure."
        let result = passwordRegex.test(newpass);
        console.info("result: " + result);
        return false;
    }
    return true;
}
function checkConfirm(event) {
    let confirmPass = document.getElementById("confirmPassword").value;
    let newPass = document.getElement("newPassword").value;
    if (newPass != confirmPassword)) {
        feedback.innerHTML = "Password does not match.";    
        return false;
    }
    return true;
}
let feedback - document.getElementById("feedback");

function newUserRequest() {

}

function checkUser() {
    let email = document.getElementById(emailUser).value;
    let password = document.getElementById("passwordUser").value;

}

<div class = "itemsFormDisplay">
    <label class = "detailNames">Password</label><br>
    <input id = "newPassword" class = "detailsFields" type = "password" name = "password" required>
</div>

<div class = "itemsFormDisplay">
    <label class = "detailNames">ConfirmPassword</label><br>
    <input id = "confirmPassword" class = "detailsFields" type = "password" name = "password" required>
</div>