Return False not working inside jQuery.ajax

Question

P.S.: Read \"EDITED on 2019-06-29\":

I have a webform for updating user information, and when he updates his email a verification is performed via

Answer 1

Seems like you don't realy get the idea jQuery. You don't need to use return false, and not there. You can call event.preventDefault();:

$('#form').submit(function(event) {
    $.get('/ajax/verify-email.php?email=' + $('#email').val(), function(d) {
        if (d == '1') {
            alert('Another user is using this email');
            $('#email').focus();
        }
    });

    event.preventDefault();
});

See this example.