Что означает такая запись

function tryLogin() {
if (sahakontrol()) {
var qS = $.url(location.href);
CookieExpires = new Date();
CookieExpires.setTime(CookieExpires.getTime() + (1000 * 60 * 60 * 24 * 365));
var newOptions = { domain: qS.data.attr.host, path: qS.data.attr.directory, expiresAt: CookieExpires };
if ($.cookies) {
if ($("#remember").attr('checked')) {
var rememberMe = { agencyCode: $("#txtAgency").val(), userCode: $("#txtUserName").val(), pass: $("#txtPassword").val() };
$.cookies.set('rememberMe', $.browser.msie ? $.json.encode(rememberMe) : rememberMe, newOptions);
}
else {
$.cookies.del('rememberMe');
}
if ($("#autoLogin").attr('checked')) {
var _autoLogin = { OK: true };
$.cookies.set('autoLogin', $.browser.msie ? $.json.encode(_autoLogin) : _autoLogin, newOptions);
} else $.cookies.del('autoLogin');
}
var loginData = '{"agencyCode":"' + $("#txtAgency").val() + '",' +
'"userName":"' + $("#txtUserName").val() + '",' +
'"pass":"' + $("#txtPassword").val() + '",' +
'"queryString":"' + qS.data.attr.query + '"}';
$.ajax({
async: false,
type: "POST",
url: "UserLogin.aspx/tryLogin",
data: loginData,
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function(msg) {
window.location = msg.d;
},
error: function(xhr, msg, e) {
if (xhr.responseText != '' && xhr.responseText != '{"d":null}')
showAlert(xhr.responseText);
},
statusCode: {
408: function() {
logout();
}
}
});
}
//sahakontrol(); string agencyCode, string userName, string pass, string queryString
}

var loginData = '{"agencyCode":"' + $("#txtAgency").val() + '",' +
'"userName":"' + $("#txtUserName").val() + '",' +
'"pass":"' + $("#txtPassword").val() + '",' +
'"queryString":"' + qS.data.attr.query + '"}';