Add Required Anti-Forgery Field Ajax Request on MVC - ajax

Question

I'm trying to do an ajax post request on my MVC app, simply post data of form to server.
but I always get this error:
The required anti-forgery form field "__RequestVerificationToken" is not present.
This is my code for ajax request:
var reservationID = document.getElementById('ReservationID').value;
var arrival = document.getElementById('Arrival').value;
var departure = document.getElementById('Departure').value;
var noofrooms = document.getElementById('NoOfRooms').value;
var guestid = document.getElementById('GuestID').value;
var rateid = document.getElementById('RateID').value;
var agencyid = document.getElementById('AgencyID').value;
var sourceid = document.getElementById('SourceID').value;
var reservationtype = document.getElementById('ReservationType').value;
var reservation = { ReservationID: reservationID, Arrival: arrival, Departure: departure, NoOfRooms: noofrooms, GuestID: guestid, RateID: rateid, AgencyID: agencyid, SourceID: sourceid, ReservationTypeID: reservationtype };
var url = '/Reservations/Create';
$.ajax({
url: url,
type: "POST",
data : reservation,
contentType: "application/json; charset=utf-8",
success: function(data, textStatus, jqXHR) {
alert('success');
},
error: function (jqXHR, textStatus, errorThrown) {
}
});
How can I add this anti-forgery field on my ajax?

Answer 1

For me this sollution works:
<script>
#functions{
public string TokenHeaderValue()
{
string cookieToken, formToken;
AntiForgery.GetTokens(null, out cookieToken, out formToken);
return cookieToken + ":" + formToken;
}
}
$.ajax("api/values", {
type: "post",
contentType: "application/json",
data: { }, // JSON data goes here
dataType: "json",
headers: {
'RequestVerificationToken': '#TokenHeaderValue()'
}
});
</script>
taken from:
Preventing Cross-Site Request Forgery (CSRF) Attacks in ASP.NET Web API