gistfile1.js

// do not do this in a real add-on, use contentScriptFile instead.
var listener = "window.addEventListener('hashchange', function() {" +
                    "  alert(window.location.hash);" +
                    "}, false);"

var pageMod = require("sdk/page-mod").PageMod({
  include: "*.google.ca",
  contentScript: listener
});

require("sdk/tabs").open("https://google.ca");