Element.Center = function(element) {
     if($(element) != null) {
          if(typeof window.innerHeight != 'undefined') {
               $(element).style.top = 
                    Math.round(document.viewport.getScrollOffsets().top + 
                    ((window.innerHeight - $(element).getHeight()))/2)+'px';
               $(element).style.left = 
                    Math.round(document.viewport.getScrollOffsets().left + 
                    ((window.innerWidth - $(element).getWidth()))/2)+'px';
          } else {
               $(element).style.top = 
                    Math.round(document.body.scrollTop + 
                    (($$('body')[0].clientHeight - $(element).getHeight()))/2)+'px';
               $(element).style.left = 
                    Math.round(document.body.scrollLeft + 
                    (($$('body')[0].clientWidth - $(element).getWidth()))/2)+'px';
          }
     }
}