JS图片轮播的有关问题

function adjust(containerID) {

            var container = $("#" + containerID);

            var imgs = container.find("img");

            _self = this;

            _self.speed = 3;

            _self.imgs = imgs;

            _self.container = container;

            _self.width = parseInt(container.width());

            _self.length = _self.imgs.length;

            _self.imgWidth = Math.round(_self.width/_self.length);

            _self.run = function () {

                var left = Math.abs(parseInt(_self.container.css("left")));

                if (left < _self.width - _self.imgWidth) {

                    _self.container.css("left", (-left - _self.speed) + "px");

                    console.log(left);

                } else {

                    _self.container.find("img:eq(0)").appendTo(_self.container);

                    _self.container.css("left", (-left + _self.imgWidth - _self.speed) + "px");

                }

                setTimeout(function () {

                    _self.run();

                }, 33);

                }