var PauseAmount = 5000;
var NextIndex = 0;

jQuery(function () {

    jQuery("#slogan").hide();
    jQuery("#slogan span").hide();

    jQuery("#slogan span").filter(":first").show();

    Roll();
});

function Roll() {

    jQuery("#slogan").animate({
        width: ['toggle', 'swing']
    }, 1000, function () {

        if (!jQuery(this).is(":visible")) {
            var CurrentItem = jQuery("#slogan span").get(NextIndex);
            jQuery(CurrentItem).hide();

            NextIndex = GetNextIndex(NextIndex);

            var NextItem = jQuery("#slogan span").get(NextIndex);
            jQuery(NextItem).show();
        }

        var timeout = window.setTimeout(Roll, PauseAmount);
    });
}

function GetNextIndex(index) {

    if (jQuery("#slogan span").size() > index + 1)
        return index + 1;
    else
        return 0;
}