Custom email address with Bootstrap - php

Question

I have a registration form, with "Username", "Email", "Password" fields.
I would like that only email with "#mychoice.it" (it's only an example) can be used.
hitoeveryone#mychoice.it -> ok
erika#mychoice.it -> ok
anthony#gmail.it -> NO!!
It is possible? I'm using bootstrap and PHP.
This is my form:
<form method="post" action="registration.php" >
<div class="form-group" id="form-login" >
<label for="exampleInputEmail1">Indirizzo Email</label>
<input type="email" class="form-control" id="exampleInputEmail1" placeholder="nome.cognomeX#studio.unibo.it" name="Input_Email" required>
</div>
<div class="form-group" id="form-login">
<label for="exampleInputUsername1">Username</label>
<input type="name" class="form-control" id="exampleInputUsername1" placeholder="username" name="Input_Username" required>
</div>
<div class="form-group" id="form-login">
<label for="exampleInputPassword1">Password</label>
<input type="password" class="form-control" id="example_InputPassword1" name="Input_Password" placeholder="password" required>
</div>
<button type="submit" class="btn btn-default">Submit</button>
<button type="reset" class="btn btn-default" value="Reset">Reset</button>
and this is my PHP script for registration
<?php
session_start();
require 'connect.php';
if(isset($_POST['Input_Username'])) {
$username = $conn->real_escape_string($_POST['Input_Username']);
}
if(isset($_POST['Input_Email'])) {
$email = $conn->real_escape_string($_POST['Input_Email']);
}
if(isset($_POST['Input_Password'])) {
$password = $conn->real_escape_string($_POST['Input_Password']);
}
$sql = "INSERT INTO utente (Email, Username, Password) VALUES ('$email', '$username', '$password')";
$result = $conn->query($sql);
$conn->close();
header("location:prova.php");
?>

Answer 1

<?php
session_start();
require 'connect.php';
$allowed_domains = array("example.com","example2.com");
if(isset($_POST['Input_Username'])) {
$username = $conn->real_escape_string($_POST['Input_Username']);
}
if(isset($_POST['Input_Email'])) {
$email = $conn->real_escape_string($_POST['Input_Email']);
}
if(isset($_POST['Input_Password'])) {
$password = $conn->real_escape_string($_POST['Input_Password']);
}
$email = explode("#",$email);
if (in_array($email[1],$allowed_domains)) {
$sql = "INSERT INTO utente (Email, Username, Password) VALUES ('$email', '$username', '$password')";
$result = $conn->query($sql);
$conn->close();
header("location:prova.php");
}else{
DO SOMETHING ELSE HERE
}
?>