Animate a bike or something

animate.js

function backgroundPosition(obj){
    bgPos = obj.css('background-position');
    if(typeof(bgPos) === 'undefined') { bgPos = obj.css('background-position-x') + ' ' + obj.css('background-position-y') };

    return bgPos;
}
    var bike = $("#bike");
    var currentPos = parseInt(backgroundPosition(bike).split(" ")[0]);
    var frameWidth = parseInt(bike.outerWidth());
    var frames = currentPos/frameWidth;
    
    function animate(obj, frames, frameWidth) {
        var currentPos = parseInt(backgroundPosition(obj).split(" ")[0]);

        if (currentPos == 0) {
            obj.css('background-position', ("-"+frameWidth + 'px 0px'));
        } else if(currentPos == frames*frameWidth) {
            obj.css('background-position', ('0px 0px'));
        } else {
            var offset = currentPos-frameWidth;
            obj.css('background-position', (offset + 'px 0px'));
        }

        var t = setTimeout(function(){animate(bike, frames, frameWidth)}, 100);
    }
    
    animate(bike, frames, frameWidth);

bike.css

#bike {
    width: 530px;
    height: 294px;
    background: url("../img/bike.png") no-repeat scroll -1060px 0px transparent;
}