// ==UserScript==
// @name           ShowAmazonProductShortURL
// @namespace      http://blog.kaihatsubu.com/
// @description    double click to show product URL
// @include        http://www.amazon.co.jp/*
// ==/UserScript==
(function() {
  document.addEventListener("dblclick", function(event) {
    var baseURL = "http://www.amazon.co.jp";
    var patternA = /\/dp\/[^/]+/;
    var patternB = /\/gp\/product\/[^/]+/;
    if (location.toString().match(patternA)) {
      alert(baseURL + location.toString().match(patternA)[0]);
    } else if (location.toString().match(patternB)) {
      alert(baseURL + location.toString().match(patternB)[0]);
    }
  }, false);
})();