:User:Cunners/monobook.js

function externISBN() {

var magicURL = "http://www.amazon.com/exec/obidos/ASIN/MAGICNUMBER/wikipedia08-20";

var magicRegex = /MAGICNUMBER/ig;

if(wgPageName != "Special:Booksources" && wgPageName != "Wikipedia:Book_sources"){

for (var i = 0; i < document.links.length; i++)

{

if( document.links[i].href.match(/isbn=(.*)/) ) {

document.links[i].href=magicURL.replace(magicRegex, RegExp.$1);

}

}

}

}

$(externISBN);