Sorry to say, but problems still remain.

I have experienced a web page to work perfectly on Ubuntu/Firefox 3.6.8 while the same page fails on Windows/Firefox 3.6.8.

The problem was that the expr parameter in some cases is an integer (i.e. neither string nor function) (don't ask me why – I haven't been able to figure that out; it only happen in a single grid out of 6 in my application). In that case, the local variable prm becomes undefined and an exception is raised.

I have fixed it by initialising prm to the empty string like this: