var currentTag = 'presentation';

$(document).ready(function(){
    $('.pngfix').supersleight({shim: '/img/x.gif'});

    $('#content').load('html/presentation.html');

    $('.ajax').live('click', function(event){
        var tag = $(this).attr('href').substring(1);
        if (tag != currentTag){
            $('#content').slideUp('fast', function(){
                $('#content').load('html/'+tag+'.html', '', function(){
                    $('#content').slideDown('normal');
                });
            });
            currentTag = tag;
        }
        event.preventDefault();
    });
});