Using window.request and cancel AnimationFrame

game.js

/* Animation */
    var self = this;
    window.requestAnimFrame = (function(){
        return  window.requestAnimationFrame       ||
                window.webkitRequestAnimationFrame ||
                window.mozRequestAnimationFrame    ||
                function(callback){
                    window.setTimeout(callback, 1000 / 60); // 60 frames per sec
                };
        })();
        
    var request; // 
    var loop = function() {
        self.render();
        request = requestAnimFrame(loop);
        frame++;
        };

    loop();

    window.cancelRequestAnimFrame = ( function() {
    return window.cancelAnimationFrame          ||
        window.webkitCancelRequestAnimationFrame    ||
        window.mozCancelRequestAnimationFrame       ||
        window.oCancelRequestAnimationFrame     ||
        window.msCancelRequestAnimationFrame        ||
        clearTimeout
    } )();

    init(); // initialize settings before game begins