Please help with this javascript slideshow bug

[lisali]

Hi,

In the slide show code below, there's a function to press "previous" and "next" links. The "next" one works fine, and if you keep pressing it, it cycles through all the slides.

The "previous" one is a bit messed up, for some reason - it will go back a slide or two but then it will just go blank!

Could you please help?
Thank you!

<script type="text/javascript">
        start_slideshow(1, 3, 3000);

        var currentSlide = 1;

        function start_slideshow(start_frame, end_frame, delay) {
            id = setTimeout(switch_slides(start_frame,start_frame,end_frame, delay), delay);
        }

        function switch_slides(frame, start_frame, end_frame, delay) {
            
            return (function() {
                             
                Effect.Fade('slide' + frame, { duration: 1.0 });
                
                if (frame == end_frame) {
                    frame = start_frame; 
                    currentSlide = frame;
                } else {
                    frame = frame + 1; 
                    currentSlide = frame;
                }
                
                Effect.Appear('slide' + frame, { duration: 1.0 });
                
                if (delay == 1000) {
                    delay = 3000; 
                }
                
                id = setTimeout(switch_slides(frame, start_frame, end_frame, delay), delay);
            })
        }

        function stop_slideshow() {
            clearTimeout(id);
        }
        
        function next_slide() {
            
            clearTimeout(id);

            Effect.Fade('slide' + currentSlide, { duration: 1.0 });
            
            if (currentSlide == 4) {
                currentSlide = 0;
            }
            
            currentSlide = currentSlide + 1;
            Effect.Appear('slide' + currentSlide, { duration: 1.0 });
            id = setTimeout(switch_slides(currentSlide, currentSlide, currentSlide, delay), delay);
        }
        
        function previous_slide() {
            
            clearTimeout(id);
            
            if (currentSlide == 0) {
                currentSlide = 1;
            } else {
              Effect.Fade('slide' + currentSlide, { duration: 1.0 });
              
              currentSlide = currentSlide - 1;
              Effect.Appear('slide' + currentSlide, { duration: 1.0 });
              id = setTimeout(switch_slides(currentSlide, currentSlide, currentSlide, delay), delay);
            }
        }
        
    </script>

The previous/next links are like this:

<a href="#" onclick="next_slide()">Next</a>
<a href="#" onclick="previous_slide()">Previous</a>

[Fang]

Try in previous_slide:

            if (currentSlide == 0) {
                currentSlide = 4;

[lisali]

Try in previous_slide:

            if (currentSlide == 0) {
                currentSlide = 4;

Hi Fang - many thanks for your reply. I tried that, it did not make any difference, unfortunately

Thanks!

[Fang]

Do you have a 'working' example?

[lisali]

Hi Fang,

Many thanks for your reply.

Here's an example:

http://www.sixia.com/index.html

If you click the "next" button a couple of times, it's fine. But if you click the "previous" button and go before the first slide, it's blank...

It also seems if you click the "next" button too fast, it will go blank too??

Thanks!

[Fang]

delay hasn't been defined

[lisali]

Hi - how do I do that?