Many languages have letters that only differ from each other by an accent or another sign, especially vowels.
If one wants to replace those vowels so that the ones with a sign are replaced with the corresponding base character there is the need of a table to easily perform the replacement.
I would like to know
1) if this table is available, in a thorough form for most languages.
Or
2) if programming languages have a string utility function to perform the same operation (I need it in Javascript, especially for vowels).