var startItem = 0;
var oldItem = 4;

function setHighlight(){
    if (startItem == 4) {
        startItem = 1;
        oldItem = 4;
    }
    else {
        oldItem = startItem;
        startItem++;
    }
    
    var nextnavfragment = 'nav-fragment-' + startItem;
    var oldnavfragment = 'nav-fragment-' + oldItem;
    var nextfragment = 'fragment-' + startItem;
    var oldfragment = 'fragment-' + oldItem;

    $("li[id='" + oldnavfragment + "']").removeClass('ui-tabs-selected ui-state-active');
    $("li[id='" + oldnavfragment + "']").addClass('ui-state-default');
    $("li[id='" + nextnavfragment + "']").addClass('ui-tabs-selected ui-state-active');
    $("li[id='" + nextnavfragment + "']").removeClass('ui-state-default');

    $("div[id='" + oldfragment + "']").fadeTo(800, 0.0).addClass('ui-tabs-hide');
    $("div[id='" + nextfragment + "']").removeClass('ui-tabs-hide').fadeTo(800, 1.0);
}

$(document).ready(function(){
    $("div[id='fragment-1']").css('opacity', 1);
    $("div[id='fragment-2']").css('opacity', 0);
    $("div[id='fragment-3']").css('opacity', 0);
    $("div[id='fragment-4']").css('opacity', 0);
    setInterval( "setHighlight()", 8000 );
});