docs: function initViewerHTML() {
          // create viewer HTML
          $el.html(Crocodoc.viewerTemplate);
          if (config.useWindowAsViewport) {
              config.$viewport = $(window);
              $el.addClass(CSS_CLASS_WINDOW_AS_VIEWPORT);
          } else {
              config.$viewport = $el.find('.' + CSS_CLASS_VIEWPORT);
          }
          config.$doc = $el.find('.' + CSS_CLASS_DOC);
      }