code: function() {
          var index = this.options.zIndex || ++currentIndex;
  
          this.$mask.css({
              zIndex: index - 1
          }).show();
  
          this.$container.css({
              zIndex: index
          }).show();
  
          if (this.options.position === 'absolute') {
              this.$container.css({
                  top: this.$container.position().top + document.body.scrollTop
              });
          }
      }
docs: 打开对话框