Click on button, change user status to active in field and send this user automatically e-mail - email

Question

I have the code to update the user in the application that updates the user in the database.
My problem is that when I click on the button aktivan = active (when the user is registered there status neaktivan = inactive, so I'm as administrators have to approve) to automatically send e-mail to that he was active?
<div class="control-group <?php echo !empty($status_racunaError)?'error':'';?>">
<label class="control-label">Status računa:</label>
<div class="controls">
<input name="status_racuna" id="status_racuna" type="text" placeholder="Status računa" value="<?php echo !empty($status_racuna)?$status_racuna:'';?>"> &nbsp
<button name="btn-upload" type="submit" id="btn-upload" class="btn btn-success" onclick="aktivan()"><i class="glyphicon glyphicon-send"></i> aktivan</button>
&nbsp <button type="button" onClick="neaktivan()" class="btn btn-danger">neaktivan</button>
<?php if (!empty($emailError)): ?>
<span class="help-inline"><?php echo $status_racunaError;?></span>
<?php endif;?>
</div>
</div>
<div class="form-actions">
<button type="submit" class="btn btn-success">Ažuriraj</button>
<a class="btn" href="admin_zona.php">Nazad</a>
</div>
</form>
</div>
The screenshot is below
I wrote this code for sending e-mail, but I do not know whether to call it from a new file or can call within the same (update.php)
echo "<div class=\"poruka_korisnik\"><p>Email je poslan na korisnikovu adresu. <i>$_POST[email]</i>. Molimo Vas da provjerite svoj e-mail.</p></div>";
$to = $_POST['email'];
$subject = "OPG Burza: obavijest o registraciji";
$message = "Dobrodošli!\r\r Hvala Vam što ste se registrirali na OPG Burzu. Vaš zahtjev za registracijom je odobren. Možete pristupiti našoj stranici na poveznici www.opg-burza.com.";
$headers = 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=UTF-8' . "\r\n";
$headers .= 'From: OPG Burza team <noreply#opg-burza.com>' . "\r\n";
mail($to, $subject, $message, $headers);
}
I tried in every way, the new script, but something did not set well.
Any ideas or how to accurately define a script that sends e-mail just this particular user and can be from the same file update.php send the mail?

Answer 1

What is behind your
neaktivan()
aktivan()
function?
Js, background php code, etc
Try this before the form to handle the post:
<?php
if (isset($_POST['status_racuna']) && isset($_POST['user_id'])) {
#do some validation here
$status_racuna = $_POST['status_racuna'];
$user_id = $_POST['user_id'];
$sql="UPDATE users SET activ= '{$status_racuna}' where id={$user_id}";
$updated = $db->query($sql);
if ($updated) {
#display success message
# send mail
} else {
# display the error message
}
}
?>
I cannot see you opened the form or not.
and add hidden input with name user_id.