Adding basic JQuery animation

Adding basic JQuery animation

I have been playing with a bit of code I found of the web and it works well, it basicly allows me to create pages and navigate between them all done via JQuery. The one question I have is, how hard is it to add some simple animation to it, such as fadein which if I have read correctly is built into JQuery?

I will post the code below and if there is anyone out there that is able to help it would be much apreciated. I look forward to any response to help me move this forward :)

Ludz~

  1. <?php $portfolionum=get_option('portfolionum'); ?>
    <script type="text/javascript">
    $(document).ready(function(){
       
        //how much items per page to show
        var show_per_page = '<?php echo $portfolionum; ?>';
        //getting the amount of elements inside content div
        var number_of_items = $('#content').children().size();
        //calculate the number of pages we are going to have
        var number_of_pages = Math.ceil(number_of_items/show_per_page);
       
        //set the value of our hidden input fields
        $('#current_page').val(0);
        $('#show_per_page').val(show_per_page);
       
        //now when we got all we need for the navigation let's make it '
       
        /*
        what are we going to have in the navigation?
            - link to previous page
            - links to specific pages
            - link to next page
        */
        var navigation_html = '<div class="folionav"><a class="previous_link" href="javascript:previous();">Prev</a>';
        var current_link = 0;
        while(number_of_pages > current_link){
            navigation_html += '<a class="page_link" href="javascript:go_to_page(' + current_link +')" longdesc="' + current_link +'">'+ (current_link + 1) +'</a>';
            current_link++;
        }
        navigation_html += '<a class="next_link" href="javascript:next();">Next</a></div>';
       
        $('#page_navigation').html(navigation_html);
       
        //add active_page class to the first page link
        $('#page_navigation .page_link:first').addClass('active_page');
       
        //hide all the elements inside content div
        $('#content').children().css('display', 'none');
       
        //and show the first n (show_per_page) elements
        $('#content').children().slice(0, show_per_page).css('display', 'block');
       
    });

    function previous(){
       
        new_page = parseInt($('#current_page').val()) - 1;
        //if there is an item before the current active link run the function
        if($('.active_page').prev('.page_link').length==true){
            go_to_page(new_page);
        }
       
    }

    function next(){
        new_page = parseInt($('#current_page').val()) + 1;
        //if there is an item after the current active link run the function
        if($('.active_page').next('.page_link').length==true){
            go_to_page(new_page);
        }
       
    }
    function go_to_page(page_num){
        //get the number of items shown per page
        var show_per_page = parseInt($('#show_per_page').val());
       
        //get the element number where to start the slice from
        start_from = page_num * show_per_page;
       
        //get the element number where to end the slice
        end_on = start_from + show_per_page;
       
        //hide all children elements of content div, get specific items and show them
        $('#content').children().css('display', 'none').slice(start_from, end_on).css('display', 'block');
       
        /*get the page link that has longdesc attribute of the current page and add active_page class to it
        and remove that class from previously active page link*/
        $('.page_link[longdesc=' + page_num +']').addClass('active_page').siblings('.active_page').removeClass('active_page');
       
        //update the current page input field
        $('#current_page').val(page_num);
    }
     
    </script>