I am working on ChatApp by Php ,MySQL and javascript
But i face alot of errors
now when i am trying to make the error text give me the right error message there somthing happens and i can`t understand (i have added an picture)
please any one can help!!!

The code error:
Uncaught TypeError: Cannot read properties of null (reading ‘style’)

i am trying to make the error text give me the right error message like this :

signup.js:

const form = document.querySelector(".signup form"),
    continueBtn = form.querySelector(".button input"),
    errorText = form.querySelector(".error-text");

form.onsubmit = (e) => {
    e.preventDefault();
}

continueBtn.onclick = () => {
    let xhr = new XMLHttpRequest();
    xhr.open("POST", "php/signup.php", true);
    xhr.onload = () => {
        if (xhr.readyState === XMLHttpRequest.DONE) {
            if (xhr.status === 200) {
                let data = xhr.response;
                if (data === "success") {
                    location.href = "users.php";
                } else {
                    errorText.style.display = "block";
                    errorText.textContent = data;
                }
            }
        }
    }
    let formData = new FormData(form);
    xhr.send(formData);
}

signup.php:

<?php 
       session_start();
    include_once "config.php";
    $fname = mysqli_real_escape_string($conn, $_POST['fname']);
    $lname = mysqli_real_escape_string($conn, $_POST['lname']);
    $email = mysqli_real_escape_string($conn, $_POST['email']);
    $password = mysqli_real_escape_string($conn, $_POST['password']);
    if(!empty($fname) && !empty($lname) && !empty($email) && !empty($password)){
        if(filter_var($email, FILTER_VALIDATE_EMAIL)){
            $sql = mysqli_query($conn, "SELECT * FROM users WHERE email = '{$email}'");
            if(mysqli_num_rows($sql) > 0){
                echo "$email - This email already exist!";
            }else{
                if(isset($_FILES['image'])){
                    $img_name = $_FILES['image']['name'];
                    $img_type = $_FILES['image']['type'];
                    $tmp_name = $_FILES['image']['tmp_name'];
                    
                    $img_explode = explode('.',$img_name);
                    $img_ext = end($img_explode);
    
                    $extensions = ["jpeg", "png", "jpg"];
                    if(in_array($img_ext, $extensions) === true){
                        $types = ["image/jpeg", "image/jpg", "image/png"];
                        if(in_array($img_type, $types) === true){
                            $time = time();
                            $new_img_name = $time.$img_name;
                            if(move_uploaded_file($tmp_name,"images/".$new_img_name)){
                                $ran_id = rand(time(), 100000000);
                                $status = "Active now";
                                $encrypt_pass = md5($password);
                                $insert_query = mysqli_query($conn, "INSERT INTO users (unique_id, fname, lname, email, password, img, status)
                                VALUES ({$ran_id}, '{$fname}','{$lname}', '{$email}', '{$encrypt_pass}', '{$new_img_name}', '{$status}')");
                                if($insert_query){
                                    $select_sql2 = mysqli_query($conn, "SELECT * FROM users WHERE email = '{$email}'");
                                    if(mysqli_num_rows($select_sql2) > 0){
                                        $result = mysqli_fetch_assoc($select_sql2);
                                        $_SESSION['unique_id'] = $result['unique_id'];
                                        echo "success";
                                    }else{
                                        echo "This email address not Exist!";
                                    }
                                }else{
                                    echo "Something went wrong. Please try again!";
                                }
                            }
                        }else{
                            echo "Please upload an image file - jpeg, png, jpg";
                        }
                    }else{
                        echo "Please upload an image file - jpeg, png, jpg";
                    }
                }
            }
        }else{
            echo "$email is not a valid email!";
        }
    }else{
        echo "All input fields are required!";
   }
?>