code: function initVar() {
          $slideTip = $$(defaultOptions.tipID);
          $container = $$(defaultOptions.containerID);
          slideWidth = defaultOptions.width;
          slideHeight = defaultOptions.height;
          $progress = $$(defaultOptions.progressID);
          Slide.$slides = $slides = toArray($(defaultOptions.slideClass, $container));
  
          slideCount = $slides.length; //幻灯片总页数-1
          Slide.count = slideCount;
  
          // $container.style.width = slideCount*slideWidth + 'px';//设置容器总宽度
          slideCount--;
          $drawBoard = $$(defaultOptions.drawBoardID);
          if ($drawBoard) {
              $drawBoard.style.display = 'none';
          }
      }
docs: 初始化变量