(function () {
    var log = {
        debug: function (category, message) {
            this.append(category, message, "debug");
        },

        error: function (category, message) {
            this.append(category, message, "error");
        },

        append: function (category, message, level) {
            // do nothing by default
        }
    };

    window.log = log;
})();