Brian Dunning's FileMaker Custom Functions

ISBN13Check ( ISBN13 ; text )

validates ISBN-13

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Larry Nichols   Larry Nichols

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  Sample input:
ISBN13Check ( 9780131986472 ; "Invalid!" )
  Sample output:
Invalid! (number should be 9780131986473)

  Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

For booksellers and others who need to validate their 13-digit ISBNs during data entry, this function checks a number against the industry calculation for ISBN13s and outputs a warning message of your choice if validation fails. I recommend nesting the TextColor () function in the second parameter to make the warning message more eye-catching.



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Note: these functions are not guaranteed or supported by Please contact the individual developer with any questions or problems.

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