If anyone is interested you’ll find it at http://www.phpclasses.org/browse/package/1707.html

It’s just called ISBNcheck (not a clever name, but it works)

kapn

http://tinyurl.com/28ncrk

Lines like this: for($i = 1; $i genchksum10($isbn2);

and blocks of code that end like this:

function isbn_genchksum13($isbn) {
$isbn = trim($isbn);
for ($i = 0; $i

Surely can’t be correct. What is going on here? Is everyone just not good at copy and pasteing? Am I the idiot? I’m baffled.

I poked around the site and didn’t see a guide for the 13 digit numbers. I assume its the same as 10, except with the dash added after the opening 978.

I will update my function when I have some free time, and I’ll post the code here.

Hyphenation Instructions

I added the isnb_dashes($isbn) function, which accepts a 10 or 13 digit ISBN number and adds the dashes. This does not check the validity of the string, it just returns it. If it isn’t 10 or 13 characters long, the function returns false.


function isbn_convert($isbn) {
$isbn2 = substr("978" . trim($isbn), 0, -1);
$sum13 = isbn_genchksum13($isbn2);
$isbn13 = "$isbn2-$sum13";
return ($isbn13);
}

## ISBN Add Dashes
function isbn_dashes($isbn) {
switch(strlen($isbn)):
case 13:
return
substr($isbn,0,3).”-”
.substr($isbn,3,1).”-”
.substr($isbn,4,3).”-”
.substr($isbn,7,5).”-”
.substr($isbn,12,1);
break;
case 10:
return
substr($isbn,0,1).”-”
.substr($isbn,1,3).”-”
.substr($isbn,4,5).”-”
.substr($isbn,9,1);
break;
default: return false; break;
endswitch;
}


Parse error: syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or ‘}’ in /usr/home/www/htdocs/test/ISBN_script.php on line 11

so I changed public function to function and (not surprisingly)

Fatal error: Undefined class name ’self’ in /usr/home/www/htdocs/test/ISBN_script.php on line 13

Thanks for producing this, I found a javascript version, but wanted a PHP version for my site.

This code has saved me a lot of time.

Thanks again!

So, if I’m right, the isbn_gettype should be :
function isbn_gettype($isbn) {
$isbn = trim($isbn);
if (preg_match(’%[0-9]{13}?%s’, $isbn)) {
if (isbn_validatettn($isbn)==1){
return 13;
} else {return(-1);}

} else if (preg_match(’%[0-9]{9}?[0-9Xx]%s’, $isbn)) {
if (isbn_validateten($isbn)==1){
return 10;
} else {return -1;}
} else {
return -1;
}
}

and the isbn_validatettn function should be :

function isbn_validatettn($isbn) {
$isbn = trim($isbn);
$chksum = substr($isbn, -1, 1);
$isbn = substr($isbn, 0, -1);
$sum = isbn_genchksum13($isbn);
if ($chksum == $sum){
return 1;
}else{
return 0;
}
}