jQuery.fn.center = function(loaded) {
    var obj = this;
    body_width = parseInt($(window).width());
    body_height = parseInt($(window).height());
    block_width = parseInt(obj.width());
    block_height = parseInt(obj.height());
    
    left_position = parseInt((body_width/2) - (block_width/2)  + $(window).scrollLeft());
    if (body_width < block_width) { left_position = 0 };
    top_position = parseInt((body_height/2) - (block_height/2) + $(window).scrollTop());
    if (body_height < block_height) { top_position = 0 };
    
    if(!loaded) {
        
        obj.css({'position': 'absolute'});
        obj.css({'left': left_position, 'top': top_position});
        $(window).bind('resize', function() { 
            obj.center(!loaded);
        });
        $(window).bind('scroll', function() { 
            obj.center(!loaded);
        });
        
    } else {
        obj.stop();
        obj.css({'position': 'absolute'});
        obj.animate({'left': left_position, 'top': top_position}, 200, 'linear');
    }
}