Strange problem on some client's browsers

Question

We are fighting a strange problem on the company that I work.

We created a site of a promotion to a client where its consumers can register products barcodes to win prizes. The site was created using PHP and MySQL. The site uses SSL on every form.

However, some consumers report to the client's call-center they was no able make a registration at the site.

We try everything, but we cannot, by no ways, reproduce the problem. The consumers reported the problem on several browsers ranging from IE8 to Firefox, the problem is same on everyone them.

One co-woker this weekend was able to catch this same bug on his wife's notebook and brought her computer to the company so we could test. However, here on the company the problem didn't happened and we can make the registration normally.

We suppose this problem could be a matter of encoding and special characteres like ã and ç. But we are sure that all source files are UTF8- with BOM. We also suspect of MSXml version, but we are note sure anymore.

Because of legal impediments the client cannot ask the consumers to install anything on they computers to test or fix the problem.

Sorry but by complience rules we also cannot share the url of the site, what is a pity. I know it is too much on vacuun, but perhaps you could had crossed something similar.

Thank you

Answer 1

One co-woker this weekend was able to catch this same bug on his wife's notebook and brought her computer to the company so we could test. However, here on the company the problem didn't happened and we can make the registration normally.

This definitely tells you it's not a problem of browser nor of hardware. One other thing I can think of is the Internet connection. Check if the customers are using specific firewall/network configuration that can (for whatever reason) interfere with your site.

Notably, I remember people having problems to see the old version of my website if they had Norton Internet Security on.

Answer 2

Without more information its going to be tough to answer this one, unless someone has specifically run into the problem before. Since you can't duplicate the error yourself, try capturing all of the exceptions that are uncaught in your application and report them (have them emailed to yourself, logged to a file, etc).

Use: <?php set_exception_handler("customCatchFunction"); grab the backtrace, get var dumps on your session, post, get, server and start compiling enough information to be able to pinpoint the problem. When you're running a user-oriented application its always good to have a global exception handler to catch odd things that slip through the cracks of your try/catches (although it is not a replacement for proper try/catching and other error checking!).

Answer 3

The information you've provided leaves a lot to be desired in terms of identifying what has happenned here. No error message? No indication of what the user experience was? No indication of how it failed? No indication of what you found when you went looking in the logs? Indeed, no details of any investigation?

Assuming you really have exhausted every avenue to identify the problem, then I'd suggest building a watchdog in javascript to monitor what's actually going on and phone home with a diagnostic when it identifies a failure. This will be a lot simpler if you can re-engineer your registration process around ajax calls.

But we are sure that all source files are UTF8- with BOM.

eh? If your PHP code is UTF-8 with BOM, then you'll have all sorts of problems - PHP should be *ASCII. If you mean user submitted data, then why do you need users to upload a file in a such a poorly specified format to register?

HTH

C.