Instead of a div being shown, the form is sent - php

Question

The following should output a div if the data is not entered in the input fields or if the passwords don't match, but it does not happen:
<?php
$data = $_POST;
if(isset($data['action_signup'])){
$errors = array();
if(trim($data['email'])==''){
$errors[] = 'Введите email';
}
if(trim($data['login'])==''){
$errors[] = 'Введите имя пользователя';
}
if($data['password']==''){
$errors[] = 'Введите пароль';
}
if($data['enterpassword'] != $data['password']){
$errors[] = 'Пароль введен не верно';
}
if(empty($errors)){
//Все заебись
}else{
echo '<div class="error_div">'.array_shift($errors).'</div>';
}
}
?>
Form:
<form action="/Register.php" method="post">
<div class="containerForTextRegister"><a class="register">РЕГИСТРАЦИЯ</a>
</div>
<div class="container_inputs">
<input class="register_input_email" name="email" placeholder="e-mail" required type="email" maxlength="40" value="<?php echo #$data['email'];?>">
<input class="register_input_login" name="login" placeholder="login" required maxlength="12" value="<?php echo #$data['login'];?>">
<input class="register_input_password" name="password" placeholder="password" required pattern="^[a-zA-Z]+$" maxlength="30">
<input class="register_input_enterpassword" name="enterpassword" placeholder="enter password" required pattern="^[a-zA-Z]+$" maxlength="30">
<div class="buttons_container">
<button class="button_entrance"><a class="text_button_entrance">войти</a></button>
<button class="button_register"><a class="text_button_register" name="action_signup">регистрация</a></button>
</div>
</div>
</form>
A div window should appear, but the data is just sent and that’s it. Help, I will be very grateful

Answer 1

You have to change your html code <button class="button_register"><a class="text_button_register" name="action_signup">регистрация</a></button> to
Or
if(isset($data['action_signup'])) to if(isset($data['email']))
like
<?php
$data = $_POST;
if(isset($data['email'])){
$errors = array();
if(trim($data['email'])==''){
$errors[] = 'Введите email';
}
if(trim($data['login'])==''){
$errors[] = 'Введите имя пользователя';
}
if($data['password']==''){
$errors[] = 'Введите пароль';
}
if($data['enterpassword'] != $data['password']){
$errors[] = 'Пароль введен не верно';
}
if(empty($errors)){
//Все заебись
}else{
echo '<div class="error_div">'.array_shift($errors).'</div>';
}
}
?>