https://www.choubunsha.com/js/transisbn.js

1$(function() {
2    var getURLfromISBN13 = function(isbn13, type) {
3        var isbn10 = transISBN13To10(isbn13);
4        if (!isbn10) { 
5            return false; 
6        }
7
8        var urlBase;
9        switch (type) {
10            case 'honto':
11            default:
12                return urlBase = 'http://honto.jp/redirect.html?bookno=978' + isbn10.substring(0, isbn10.length - 1);
13                break;
14            case 'amazon':
15                return urlBase = 'http://www.amazon.co.jp/dp/' + isbn10;
16                break;
17            case 'rakuten':
18                return 'http://search.books.rakuten.co.jp/bksearch/dt?g=001&bttl=&bathr=&bpbls=&bsize=&bisbn='+ isbn10 +'&v=2&s=1&b=2';
19                break;
20        }
21    };
22
23    var transISBN13To10 = function(isbn13) {
24        var nine = isbn13.substr(3, 9);
25        
26        if (nine.length === 9) {
27            var sum = 0;
28            for (var i = 0; i < 9; i++) {
29                var dgt = 10 - i;
30                sum += ~~(nine[i]) * dgt;
31            }
32            var chkDgt = 11 - (sum % 11);
33            if (chkDgt === 10) chkDgt = 'X';
34            if (chkDgt === 11) chkDgt = '0';
35            return nine + chkDgt;
36        } else {
37            return false;
38        }
39    };
40
41    $('a.outbound').each(function() {
42        var isbn13 = $(this).data('isbn').toString();
43        var site = $(this).data('site').toString();
44        var url = getURLfromISBN13(isbn13 ,site);
45        $(this).attr('href', url);
46    });
47});