Firebug always shows GET NULL - 404 not found

Question

This is happen everytime where basic slideshow is used, no matter what kind of website.
Ffirebug / google developer tool both shows that error...
This is happen only with that specific slideshow module
example here:
http://lovemyweb.net/bug.html

Answer 1

Hi kolazero,
We've seen this come up a few times, so I figured I'd take the time to address this as directly as possible. I'll go into a fair amount of detail so you can understand exactly why it is happening, but the most important take away from this should be that this issue is harmless, and can be ignored.
Now, we don't say that lightly. Normally any errors popping up on your sites are very high priority issues for us, and ones we investigate closely, but in this particular case, this is a "error by design" sort of error. We are actually aware that this error will pop up on certain browsers, we know where in the code it occurs, and we know why it happens. In fact, in that code, the engineer who implemented this left a very large comment to anyone else who came along later explaining exactly what happens, and why it happens so that there was no confusion on the matter.
Let's get technical for a minute here. Slideshows are a bit special because they are a set of images where only 1 image is loading at a time (plus any thumbnails), so we handle them a bit differently than we do other images. When you place an image in the page using just the File > Place command, we simply insert that onto the page and let the browser handle the loading of that image all on its own. However, for slideshows, we know that there are slightly different rules we can use to improve loading times and user experience, and we take advantage of that in special code we use. If we let the browser load the images, and you had your slideshow on random, then the browser will load the first image, then the second, then the third, but you may be seeing them in the reverse order, which means you may be looking at images that haven't loaded yet. To avoid this issue, we control the loading of images, the order in which they load, and when the slideshow can go to the next slide, and we do it in an optimized way for your particular slideshow and configuration.
Now, when we load images this way, we do so by loading images off the screen, waiting for them to finish, and them plugging them into the right location. This is a very common technique, and many websites and libraries out there do this same thing or something similar. When we do it, some browsers have issues with simply loading one image after another, so we use a trick and "clear" the images between each load. This saves us some headaches for older browser bugs, and also allows us to load lots of large images without your site slowing down the users machine more than is needed. However, unfortunately a side effect of this is that on some modern browsers, when we "clear" the images, they will try to load the in between state called "null". This results in the error that you are seeing in your browser console. The browser is trying to load something that doesn't exist on the server, and thus, will show the error that it doesn't exist (404).
This issue has been around for a while, and it is one we are certainly aware of. It is on our backlog to investigate alternatives to this approach, and make improvements in this area in general, but unfortunately we have not had time to circle back around to this particular problem. We do realize that this can be a bit scary to see on your site, and we want to git rid of that sooner rather than later, but given priorities on other bugs, features, and areas of the application, it hasn't made it onto an engineers plate to look at yet. And given our resources and priorities at the moment, I'm not sure I can say when we will have a fix for this by, though, again, sooner rather than later is what we'd prefer. In the meantime, as I said earlier, this error won't cause your site any harm, and can just be ignored.
Hopefully that clears things up a bit. And if you have any questions about it, feel free to ask and I will do my best to respond.
Thanks,
Andrew
Muse QE