>Hi everybody,
>I'm wondering if I'm thinking/going in the right direction and what would be the best thing to not re-invent the wheel too much.
>I'm thinking that we can create several useful more or less generic JavaScript f functions and put them in separate js file invoked from the Master page of the webiste.
>Does it sound like a good idea?

Yes.

One js files with stuff that I call on most pages, like the png fix for IE6.
Then other ones separated by what they are used for and that you only include when needed.
(My library is still pretty small but this is how I'm laying it out.)

>I have currently created few little functions such as ShowElement, HideElement, ToggleDisplay, SetValue. I'm thinking of adding CheckIfItemSelected and CheckIfNotEmpty two separate functions one for combo/lists another for textboxes.
>
>Do you think I should create 2 separate functions or better handle it in one function using case switch?

I'd probably create 2 separate functions. But this is kind of up to you I think either way would work just fine. Having them as one would make it easier to remember them, but it would make it harder to separate them into different files.