Some of my users have reported an inability to log in with certain mobile devices, such as the Nintendo 3DS and PSP web browsers. Personally, I have a 3DS and been able to reproduce the issue... but I haven't a clue how to fix it.
Basically, all I can determine is that something is wrong with the AJAX code, which is causing the form to submit to the wrong place in the wrong format.
Now, in the past I had errors with Chrome (turned out to be adware) which I was able to debug using the Developer Tools, looking at the error console, and getting the result from there.
But how would I do this for something that has no such debugging tools? It's not just game consoles, the Steam In-Game Browser is also unable to log in with my apparently faulty AJAX code.
What steps, if any, can I take to start getting to the bottom of these errors, without the use of built-in debugging tools?