NJggumXn

1jQuery(document).ready(function($) {
2    $('#registerform').find(':submit').click(function(e) {
3        if( ! isGmail( $('#user_email').val() ) ) {
4            e.preventDefault(); // Prevent the form from submitting
5            alert('You can only register with an @gmail.com email address!');
6            return false;
7        }
8    });
9});
10
11function isGmail( address ) {
12    return address.indexOf("@gmail.com", this.length - 10) !== -1;
13}