function loadvideo (videoUrl){
    $(".mainvideo").fadeOut('slow', function() {
        $('.mainvideo').html('<object type="application/x-shockwave-flash" style="width:340px; height:215px;" data="http://www.youtube.com/v/'+videoUrl+'"><param name="movie" value="http://www.youtube.com/v/'+videoUrl+'"></object>');
        $('.mainvideo').fadeIn('slow');
    });
}