Amazon to CN

amazon_to_cn.user.js

// ==UserScript==
// @name        Amazon to CN
// @namespace   CzBiX
// @include     http://www.amazon.com/*
// @version     2
// @grant       unsafeWindow
// ==/UserScript==

var window = unsafeWindow;
var $ = window.jQuery;

if (typeof $ === 'undefined') {
  // maybe not product page, ignore it
  return;
}

var link = $('link[rel="canonical"]')[0].href;
var asin = link.substr(link.indexOf('/dp/'));
var cnLink = 'http://www.amazon.cn' + asin;

var topBar = $('#nav-cross-shop-links');
topBar.append('<a target="_blank" href="' + cnLink + '">In China</a>');