a simple pace car to test how fast (or slow) your js runs

pace_car.js

/**
 * PaceCar makes it easy to test how fast (or slow) you js runs
 *
 * Example Usage:
 *
 *    // get a PaceCar ready
 *    var p = new PaceCar();
 *    // start your engines
 *    p.start();
 *    // some sample code you want to test performance of.
 *    // who doesn't like to loop for no reason?
 *    for (var i=0; i < 10000; i=i+1) {
 *      $('body').html('hi');
 *    }
 *    // stop the pacecar and print the execution time in ms
 *    p.stop(); // => 79ms
 */
;(function(exports) {
    "use strict";
    function PaceCar() {
        return this;
    }

    PaceCar.prototype.start = function() {
        this._start = (new Date()).getTime();
    };

    PaceCar.prototype.stop = function() {
        window.console.log(((new Date()).getTime() - this._start) + ' ms');
    };
    
    exports.PaceCar = PaceCar;
}(this)); // <-- this = the global object is passed as exports