Perhaps this code would be of some use:

https://vufind.svn.sourceforge.net/svnroot/vufind/trunk/web/sys/ISBN.php

- Demian

> -----Original Message-----
> From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of
> Jonathan Rochkind
> Sent: Monday, October 24, 2011 10:45 AM
> To: [log in to unmask]
> Subject: Re: [CODE4LIB] ISBN Regular Expression
> 
> John: That's not going to work, an ISBN can end in "X" as a check
> digit,
> which is not [0-9].  You are going to be rejecting valid ISBN's, you
> have a bug.
> 
> On 10/24/2011 10:40 AM, John Miedema wrote:
> > Here's a php function I use in OpenBook to test if a user has entered
> a 10
> > or 13 digit ISBN.
> >
> > //test if 10 or 13 digits ISBN
> > function openbook_utilities_validISBN($testisbn) {
> > return (ereg ("([0-9]{10})", $testisbn, $regs) || ereg ("([0-
> 9]{13})",
> > $testisbn, $regs));
> > }
> >
> >
> >
> > On Fri, Oct 21, 2011 at 1:44 PM,
> Kozlowski,Brendon<[log in to unmask]>wrote:
> >
> >> Hi all.
> >>
> >>
> >>
> >> I'm somewhat surprised that I've never had to validate an ISBN
> manually up
> >> until now. I suppose that's a testiment to all of the software out
> there.
> >>
> >>
> >>
> >> However, I now find that I need to validate both the 10-digit and
> 13-digit
> >> ISBNs. I realize there's also a check digit and a REGEX cannot check
> this
> >> value - one step at a time. Right now I just want to work on the
> REGEX.
> >>
> >>
> >>
> >> Does anyone know the exact specifications of both forms of an ISBN?
> The
> >> ISBN organization's website didn't seem to be overly clear to me.
> >> Alternatively, if anyone has a full working regular expression for
> this
> >> purpose I would definitely not mind if they'd be willing to share.
> >>
> >>
> >>
> >> The only thing I'm doing which is abnormal is that I am not
> requiring the
> >> hyphenation or spaces between numbers since some of this data will
> be coming
> >> from a system, and some will be coming from human input.
> >>
> >>
> >>
> >>
> >> Brendon Kozlowski
> >> Web Administrator
> >> Saratoga Springs Public Library
> >> 49 Henry Street
> >> Saratoga Springs, NY, 12866
> >> [518] 584-7860 x217
> >>
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> >