code: function (index) {
  			if (this.opt.useAnimation && this.opt.refresh) {
  				if (!this.items[index]) {
  					return false;
  				}
  				var steps = this.items[index].querySelectorAll('.step');
  				var lazys = this.items[index].querySelectorAll('.lazy');
  				if (steps.length > 0) {
  					for (var element of Array.prototype.slice.call(steps)) {
  						element.style.visibility = 'hidden';
  						element.style.animationName = '__' + window.getComputedStyle(element).animationName;
  					}
  				}
  				if (lazys.length > 0) {
  					for (var element of Array.prototype.slice.call(lazys)) {
  						element.style.visibility = 'hidden';
  						element.style.animationName = '__' + window.getComputedStyle(element).animationName;
  					}
  				}
  			}
  		}
docs: 重置动画状态，全部隐藏