User:Gandalf61/monobook.js

function externISBN {

var magicURL = "http://www.amazon.com/exec/obidos/ASIN/MAGICNUMBER/wikipedia08-20"; var magicRegex = /MAGICNUMBER/ig; if(mw.config.get('wgPageName') != "Special:Booksources" && mw.config.get('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);