code: function(node) {
          node = node || Y.config.doc.documentElement;
          var ret = false,
              scrollX,
              scrollY;
  
          if (node) {
              scrollX = DOM.docScrollX(node);
              scrollY = DOM.docScrollY(node);
  
              ret = DOM._getRegion(scrollY, // top
                  DOM.winWidth(node) + scrollX, // right
                  scrollY + DOM.winHeight(node), // bottom
                  scrollX); // left
          }
  
          return ret;
      }
docs: Returns an Object literal containing the following about the visible region of viewport: (top, right, bottom, left)
  @method viewportRegion
  @for DOM
  @return {Object} Object literal containing the following about the visible region of the viewport: (top, right, bottom, left)