$(function(){
    var page = 1;
    var i = 4;
    $("a.prev").click(function(){
        var content = $("#zoomcont");
        var content_list = $("#zoomcontlist");
        var v_width = content.height();
        var len = content.find("li").length;
        var page_count = Math.ceil(len / i) ;
        if( !content_list.is(":animated") ){
            if( page == page_count ){
            }else{
                content_list.animate({ top : '-='+v_width }, "slow");
                page++;
            }
        }
    });
    $("a.next").click(function(){
        var content = $("#zoomcont");
        var content_list = $("#zoomcontlist");
        var v_width = content.height();
        var len = content.find("li").length;
        var page_count = Math.ceil(len / i);
        if(!content_list.is(":animated") ){
            if(page == 1 ){

            }else{
                content_list.animate({ top : '+='+v_width }, "slow");
                page--;
            }
        }
    });
});