code: function (evt) {
          if (!this.includeXY) {
              this.clearMouseCache();
          } else if (!this.element.hasScrollEvent) {
              OpenLayers.Event.observe(window, "scroll", this.clearMouseListener);
              this.element.hasScrollEvent = true;
          }
          
          if (!this.element.scrolls) {
              var viewportElement = OpenLayers.Util.getViewportElement();
              this.element.scrolls = [
                  window.pageXOffset || viewportElement.scrollLeft,
                  window.pageYOffset || viewportElement.scrollTop
              ];
          }
  
          if (!this.element.lefttop) {
              this.element.lefttop = [
                  (document.documentElement.clientLeft || 0),
                  (document.documentElement.clientTop  || 0)
              ];
          }
          
          if (!this.element.offsets) {
              this.element.offsets = OpenLayers.Util.pagePosition(this.element);
          }
  
          return new OpenLayers.Pixel(
              (evt.clientX + this.element.scrolls[0]) - this.element.offsets[0]
                           - this.element.lefttop[0], 
              (evt.clientY + this.element.scrolls[1]) - this.element.offsets[1]
                           - this.element.lefttop[1]
          ); 
      }
docs: Method: getMousePosition
  
  Parameters:
  evt - {Event}
  
  Returns:
  {<OpenLayers.Pixel>} The current xy coordinate of the mouse, adjusted
  for offsets