$(document).ready(function () {
$(".cn_item:eq(0)").addClass("selected");
$(".cn_page").css("display", "none");
$(".cn_page:eq(0)").css("display", "block");
$(".cn_content").css("top", "330px");
$(".cn_content:eq(0)").css("top", "5px");
//caching
//next and prev buttons
var $cn_next = $('#cn_next');
var $cn_prev = $('#cn_prev');
//wrapper of the left items
var $cn_list = $('#cn_list');
var $pages = $cn_list.find('.cn_page');
//how many pages
var cnt_pages = $pages.length;
//the default page is the first one
var page = 1;
//list of news (left items)
var $items = $cn_list.find('.cn_item');
//the current item being viewed (right side)
var $cn_preview = $('#cn_preview');
//index of the item being viewed. 
//the default is the first one
var current = 1;

/*
for each item we store its index relative to all the document.
we bind a click event that slides up or down the current item
and slides up or down the clicked one. 
Moving up or down will depend if the clicked item is after or
before the current one
*/
$items.each(function (i) {
    var $item = $(this);
    $item.data('idx', i + 1);

    $item.bind('click', function () {
        var $this = $(this);
        $cn_list.find('.selected').removeClass('selected');
        $this.addClass('selected');
        var idx = $(this).data('idx');
        var $current = $cn_preview.find('.cn_content:nth-child(' + current + ')');
        var $next = $cn_preview.find('.cn_content:nth-child(' + idx + ')');

        if (idx > current) {
            $current.stop().animate({ 'top': '-300px' }, 600, 'easeOutBack', function () {
                $(this).css({ 'top': '330px' });
            });
            $next.css({ 'top': '330px' }).stop().animate({ 'top': '5px' }, 600, 'easeOutBack');
        }
        else if (idx < current) {
            $current.stop().animate({ 'top': '330px' }, 600, 'easeOutBack', function () {
                $(this).css({ 'top': '330px' });
            });
            $next.css({ 'top': '-300px' }).stop().animate({ 'top': '5px' }, 600, 'easeOutBack');
        }
        current = idx;
    });
});

/*
shows next page if exists:
the next page fades in
also checks if the button should get disabled
*/
$cn_next.bind('click', function (e) {
    var $this = $(this);
    $cn_prev.removeClass('disabled');
    ++page;
    if (page == cnt_pages)
        $this.addClass('disabled');
    if (page > cnt_pages) {
        page = cnt_pages;
        return;
    }
    $pages.hide();
    $cn_list.find('.cn_page:nth-child(' + page + ')').fadeIn();
    e.preventDefault();
});
/*
shows previous page if exists:
the previous page fades in
also checks if the button should get disabled
*/
$cn_prev.bind('click', function (e) {
    var $this = $(this);
    $cn_next.removeClass('disabled');
    --page;
    if (page == 1)
        $this.addClass('disabled');
    if (page < 1) {
        page = 1;
        return;
    }
    $pages.hide();
    $cn_list.find('.cn_page:nth-child(' + page + ')').fadeIn();
    e.preventDefault();
});
});