Deprecated. Don't use for new development and try to migrate existing uses.
This function takes a string and strips away (removes) all characters that are not part of the latin alphabet (i.e. the letters A-Z) and that are not digits.
If the string contains no alphanumeric characters at all then a value of null is returned.
It is also possible to supply a string of characters that should be excluded from being stripped.
The stripped string.