function slideSwitch() {
    var $active = $('.slItem.active');
    if( $active.length == 0 ) {
        $active = $('.slItem:last');
    }
    var $next = $active.next().length ? $active.next() : $('.slItem:first');
    $active.addClass('lastActive');
    $next.css({ opacity: 0.0 }).addClass('active').animate({ opacity: 1.0 }, 1000, function(){
        $active.removeClass('active lastActive');
    });
}

$(window).load(function(){
    if( $('#headerslider .slItem')[1] ){
        $(function() {
            setInterval( 'slideSwitch()', 5000 );
        });
    }
});