var intervalId;

$(function() {
    $(".nextScrolling").click(nextImage);
    $(".previousScrolling").click(previousImage);
    intervalId = setInterval(nextImage, 4000);
}
);

function nextImage() {
    clearInterval(intervalId);
    var currentImage = $(".JQcurrent");
    var currentImageID = currentImage.attr("id");

    var currentImageIndex = parseInt(currentImageID, 10);

    if (currentImageIndex != 5)
        currentImageIndex++;
    else
        currentImageIndex = 1;

    currentImage.fadeOut(1000);
    currentImage.removeClass("JQcurrent");
    $("#" + currentImageIndex).fadeIn(2000);
    $("#" + currentImageIndex).addClass("JQcurrent");

    intervalId = setInterval(nextImage, 4000);
    return false;
}

function previousImage() {
    clearInterval(intervalId);

    var currentImage = $(".JQcurrent");
    var currentImageID = currentImage.attr("id");

    var currentImageIndex = parseInt(currentImageID.substr(currentImageID.length - 1, currentImageID.length), 10);
   
    if (currentImageIndex != 1)
        currentImageIndex--;
    else
        currentImageIndex = 5;

    currentImage.fadeOut(2000);
    currentImage.removeClass("JQcurrent");

    $("#" + currentImageIndex).fadeIn(2000);
    $("#" + currentImageIndex).addClass("JQcurrent");

    intervalId = setInterval(nextImage, 4000);
    return false;
}