[jQuery] Can't read field value in remote method (Validation).

[jQuery] Can't read field value in remote method (Validation).


form id='f1' name='f1' method='post' action='ticket_confirm'
....
input name='field0' type='text'
input name='field1' type='text'
....
form
$(document).ready(function() {
var validator = $("#f1").validate({
    rules: {
             field0: {
                                 required: true,
                                 minlength: 9,
                                  remote: {
                                             url: "checkdocument.php",
                                             type: "get",
                                             data: { doctype: function() { return $("#field1").val
(); }
                                         }
                                     }
                                 },
I see in FireFox FireBug folowing url when debug Get method :
"checkdocument.php?field0=1234567890&doctype=undefined"
What's wrong with reading value if field1 in remote data?
Could you explain please?
Thank you.