function centerElement( element, relativeTo )
{
	if (!$defined(relativeTo) )
		relativeTo = window; 
    try
    {
        element = $(element);
        relativeTo = $(relativeTo);
    }
    catch( e )
    {
        return;
    }
    element.set('styles', {	visibility:'hidden',
						position:'absolute',
    					display:'block'});
    element.style.zIndex   = 99;

    var elSize  = element.getSize();
	var winSize = relativeTo.getSize();
	
    var setX = ( winSize.x - elSize.x ) / 2;
    var setY = ( winSize.y - elSize.y ) / 2 + relativeTo.getScroll().y;

    setX = ( setX < 0 ) ? 0 : setX;
    setY = ( setY < 0 ) ? 0 : setY;
    element.set('styles', {'left':setX + 'px',
						'top':setY + 'px',
    					'visibility':'visible'});
}