- Author: Mike White (m@mwhite.info)
- License: MIT License
PHP-Isbn is a simple class that provides methods for validating and converting between 10- and 13-digit ISBNs with a full test suite that includes some more unusual scenarios.
Be mindful of the fact that sometimes books are published with numerically invalid ISBNs due to typos, but these sometimes become official ISBNs. On the other hand, many numerically valid ISBNs exist that don't correspond to any book.
Support for hyphenating ISBNs is not included because it requires querying stored data about the meaning of parts of an ISBN. For that functionality, see, for example, this library.