Check Email Matches Specified Domain(s) Or Reject

Currently my email accepts all email domains. I would like to define which ones are allowed out of a list (solent.ac.uk, herts.ac.uk) rather than public ones such as @gmail.com etc. Whichever way is easiest for now, i'll try alternative ways for now, this is more just temporary.

I am just editing a script I bought and wanted this small change. I know it must require more than just the code I produced below to be edited but thought i'd start with something.

This is part of my registration.php page:

<form method="post" action="<?php url_for('register'); ?>">[/SIZE]
 
[SIZE=3]  <!--Email-->[/SIZE]
[SIZE=3]  <p class="email field">[/SIZE]
[SIZE=3]    <input tabindex="1" id="email" type="text" name="email" value="<?php if(isset($_POST['email'])) echo $_POST['email']; ?>" placeholder="email@example.com" autofocus />[/SIZE]
[SIZE=3]    <a href="<?php url_for('login'); ?>" tabindex="2" class="action button register" title="Click to log-in with your existing account.">Login</a>[/SIZE]
[SIZE=3]  </p>[/SIZE]
[SIZE=3]

HTML:

 

in your url_for('login'); use

if(strpos(@solent.ac.uk, $_POST['email']) {
    // Continue email script
  }else{
  echo 'Sorry, you can't register with that email address!';
}

Code (markup):

 

I ended up using this:

$whitelist = array('solent.ac.uk', 'herts.ac.uk');
list(, $domain) = array_pad(explode('@', $email, 2), 2, '');
if (!in_array($domain, $whitelist)) {
$app->flashNow('error', __('login_invalidemail'));

PHP:

Is it possible to require just the .ac.uk part instead of example.ac.uk. I want to allow all university emails only but obviously it would take hours finding every single university name and its extension ().

Would be quicker to just define/restrict to:
.ac.uk
.edu
and so on...

 

That can be a bit tricky in knowing what to do with subdomains. For instance, the following code produces the following output:

<?php
 
var_dump(getDomainExtension('example.an.cd'));
var_dump(getDomainExtension('subdomain.example.an.cd'));
 
function getDomainExtension($domain) {
    return implode('.', array_splice(explode('.', $domain), 1));
}

PHP:

string(5) "an.cd"
string(13) "example.an.cd"

Code (markup):