How do call a controller by ajax

See more:

C#

Javascript

MVC

How do call a controller by ajax i'm certain i have it right in my javascript my url looks like this --> url:

'<%: Url.Action("Contact", "HomeController") %>',

But when im debuging its not calling the controller can anyone help heres my full source,

if (error == false) {
        $.ajax({
            type: "POST",
            url: '<%: Url.Action("Contact", "HomeController") %>',
            data: data_string,
            timeout: 6000,
            error: function(request,error) {
                if (error == "timeout") {
                    $('#contact-error').slideDown('slow');
                    $('#contact-error span').text('Timed out when contacting server.');
                    setTimeout(function() {
                        $('#contact-error').slideUp('slow');
                    }, 10000);
                }
                else {
                    $('#contact-error').slideDown('slow');
                    $('#contact-error span').text('Something is not working. Please try again.');
                    setTimeout(function() {
                        $('#contact-error').slideUp('slow');
                    }, 10000);
                }
            },
            success: function() {
                $('#contact-success').slideDown('slow');
                $('#contact-success span').text('Message sent.');
                setTimeout(function() {
                    $('#contact-success').slideUp('slow');
                }, 10000);
                $('#name').val('');
                $('#contactNumber').val('');
                $('#message').val('');
            }
        });
    } else {
        $('#contact-error').hide();
        $('#contact-success').hide();
    }

And here is my controller

[HttpPost]
        public ActionResult Contact(string name, string contactNumber, string message)
        {
            try
            {
                var appSettings = new AppSettingsReader();
                var emailAddress = appSettings.GetValue("ToEmailAddress", typeof(string)).ToString();

                var mail = new MailMessage { Subject = "Digitali" };
                mail.To.Add(emailAddress);
                mail.Body = string.Format("Name: {0} <br/> Contact number: {1} <br/><br/> Message: {2} ", name, contactNumber, message);
                var mailClient = new SmtpClient();
                mailClient.Send(mail);
            }
            catch (Exception exception)
            {
                
            }
            return View();
        }