async foundation validation example

gistfile1.txt

var checkingLogin = false;
var validLogin = true;
var lastCheckedLogin = '';

var checkLogin = Debounce(function (el) {

    var code = document.location.search.match(/invite=([^&]*)/);
    var val = el.val();
    if (code) {
        code = code[1];
    }
    if (checkingLogin || lastCheckedLogin === el.val()) {
        return;
    }
    if (val === '') {
        //We're being called on the debounce tail after a bunch of backspaces
        return;
    }
    checkingLogin = true;
    lastCheckedLogin = val;
    var payload = {
        login: val,
        invite: code
    };
    var syncOptions = {
        url: App.apiUrl + '/taken',
        json: payload,
        success: function (resp) {

            checkingLogin = false;
            validLogin = !resp.data.taken;
            el.trigger('change.fndtn.abide');
        },
        error: function () {

            checkingLogin = false;
            validLogin = false;
            el.trigger('change.fndtn.abide');
        }
    };
    Sync('create', null, syncOptions);
}, 200);

//In app.init:
        $(document).foundation({
            abide: {
                validators: {
                    checkLogin: function (el, required) {


                        el = $(el);
                        if (required && el.val() === '') {
                            el.siblings('small').text('Login is required');
                            return false;
                        }
                        el.siblings('small').text('Login is taken');
                        checkLogin(el);
                        return validLogin;
                    }
                }
            }
        });