I written a code for tkae values of form in HTML and send on e-mail. So, somewhere have a mistake, can you verify this code?
   <form class="form_itself">
        <div>
            <input class="form_input" type="text" name="name" placeholder="Name *">
            <input class="form_input" type="tel" name="tel" placeholder="Contacts *">
            <button id="mybutton" type="submit" class="form_submit upper">Send request</button>
            <div class="order">Callback</div>
        </div>
    </form>
now, pure JS without other frameworks
form = document.getElementById('callBack');
formData = new FormData(form);
request = new XMLHttpRequest();
request.open("POST","sender-form.php",true);
request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
request.send(formData);
and PHP handler, please loot at all this files, where is mistake? code is beta version
<?php
 $name = $_POST['name'];
 $phone  = $_POST['tel'];
 $email="xxxx@email.ru";
 mail($email, $name, $phone);
?>
 
    