unloadElements: function (a) {
            var b, c, d;
            for (b in this.elements)this.elements.hasOwnProperty(b) && (d = Math.abs(a - b), d > this.options.preloadRange && d + this.options.preloadRange < this.num && (c = this.slides[b], c.removeChild(c.firstChild), delete this.elements[b]))
        },