function gotoPage(id, p) {
    var imgPathB = '/Content/images/gallery_arrow01',
        imgPathF = '/Content/images/gallery_arrow02';
   
    var $wrapper= $('#' + id),
        $slider = $wrapper.find('> ul'),
        $items = $slider.find('> li'),
        $images = $slider.find('img'),
        $itemsWidth = 0;

    var currentPage = parseInt($slider.attr("currentPage"));
    
    $items.each(function() { $itemsWidth += $(this).width() + 1 })

    var visible = $wrapper.width(),
        pages = Math.ceil($itemsWidth / visible);

    var page = currentPage + p;
    if (page > pages || page < 1) { return false; }
    
    var dir = page < currentPage ? -1 : 1,
        n = Math.abs(currentPage - page),
        left = dir * visible * n;
        
    if (page == pages || page == 1)
        left = dir * ($itemsWidth - visible * (pages - 1));

    //alert($itemsWidth + '--' + left + '--' + page);

    var iback = $('#' + id + '_back'),
        iforward = $('#' + id + '_forward');

    iback.removeClass('pointer');
    iforward.removeClass('pointer');
    
    $slider.animate({ left: '-=' + left }, 500, function() {
        if (page == 1) {
            iback.attr("src", imgPathB + '_n.gif');
            iforward.attr("src", imgPathF + '_a.gif');
            iforward.addClass('pointer');
        } else if (page == pages) {
            iback.attr("src", imgPathB + '_a.gif');
            iforward.attr("src", imgPathF + '_n.gif');
            iback.addClass('pointer');
        }
        else {
            iback.attr("src", imgPathB + '_a.gif');
            iforward.attr("src", imgPathF + '_a.gif');
            iforward.addClass('pointer');
            iback.addClass('pointer');
        }
        $slider.attr("currentPage", page);
    });
}