User:Chapman~enwiki/monobook.js

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