I started receiving this unknown error on Firefox’s Firebug developer tool, and for couple of hours, I could not figure out as to what this was, and I have a habit of switching gears and start working on something else if I hid road blocks in programming and when I looked closely at my script after some other work, I noticed that I had a variable defined twice, and strangely, because this issue was issue inside a function which was part of a jQuery Dialog and the function was attached to a button click function. All my try-catch functions were out the window and unable to capture this strange issue.
I thought this makes no sense, I have the programming helper plugins which will highlight, that I have defined a same name variable twice, but in this case, it seems those plugins fail to alert.
Try and Catch are good practices but they do not display clear messages specially when humans make silly mistakes
Have a nice day!