Requests Drupal 7 Services token automatically, saves it to local storage and allows to use jQuery.request() function without to worry about whether token is still valide or has to be requested again.

request.js

(function ($) {
	var token, request = null;
	$.token = function () {
		return $.get("/services/session/token").done(function (data) {
			localStorage.setItem("X-CSRF-Token", data);
			token = data;
		});
	};
	$.request = function (settings, deferred) {
		var response = deferred || $.Deferred();
		settings = $.extend(settings || {}, {
			complete: function (xhr, status) {
				switch (xhr.status) {
					case 200:
						response.resolve($.parseJSON(xhr.responseText));
						break;
					case 401:
						if (!request) request = $.token();
						request.done(function () {
							$.request(settings, response).fail(response.reject);
							request = null;
						});
						break;
					default: response.reject(xhr.status);
				}
			},
			headers: $.extend(settings.headers || {}, {
				"X-CSRF-Token": token
			}),
			type: settings.type || "post"
		})
		$.ajax(settings);
		return response;
	};
	token = localStorage.getItem("X-CSRF-Token");
	if (!token) $.token();
})(jQuery);