simple browser auto refresh

gistfile1.js

//require jquery1.6
//i wish no-dependencies
/**
 * AutoReloader.js
 * auto reload browser if files were modified.
 */
(function() {
    var TARGET_FILES = [location.href];
    var INTERVAL = 500;

    var counter = 0;
    var initPollCount = 0;
    var isBusy = false;

    /**
     * reload browser
     * @name reload
     * @function
     */
    var reload = function() {
        location.reload();
    };

    /**
     * polling
     * @name polling
     * @function
     */
    var polling = function() {
        var id = setInterval(function() {
            if (!isBusy) {
                checkUpdate(counter);
                if (counter < TARGET_FILES.length - 1) {
                    counter++;
                } else {
                    counter = 0;
                }
            }
        }, INTERVAL);
    };

    /**
     * check update
     * @name checkUpdate
     * @function
     * @param index 
     */
    var checkUpdate = function(index) {
        isBusy = true;
        var fileName = TARGET_FILES[index];
        $.ajax({
            type: "GET",
            ifModified: true,
            url: fileName,
            success: function(data) {
                if (initPollCount > TARGET_FILES.length) {
                    if (data) {
                        reload();
                    }
                } else {
                    initPollCount++;
                }
                isBusy = false;
            },
            error: function() {
                isBusy = false;
            }
        });
    };

    //define interface
    window.AutoReloader = {
        add: function() {
            for (var i = 0; i < arguments.length; i++) {
                TARGET_FILES.push(arguments[i]);
            }
        }
    };

    //entry point
    polling();
})();