User:Zshortman/monobook.js

function externISBN { for (var i = 0; i < document.links.length; i++) {              if( document.links[i].href.match(/isbn=(.*)/) ) { document.links[i].href='http://www.amazon.com/exec/obidos/ASIN/'+RegExp.$1; }   }

}

addOnloadHook(externISBN); // User:Lupin/popups.js

mw.loader.load(            'https://en.wikipedia.org/w/index.php?title=User:Lupin/popups.js'             + '&action=raw&ctype=text/javascript&dontcountme=s');