Greasemonkey User Script: ensure that you are on smile.amazon.com.

smile_amazon_com.user.js

// ==UserScript==
// @name         smile_amazon_com
// @namespace    http://orderthruchaos.bitbucket.org/
// @copyright    2015+, Brett DiFrischia
// @license      
// @description  Always remember to smile!
// @grant        GM_log
// @require      https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js
// @include      http://www.amazon.com/*
// @include      https://www.amazon.com/*
// @include      http://amazon.com/*
// @include      https://amazon.com/*
// ==/UserScript==


this.$J = this.jQuery = jQuery.noConflict(true);


(
  function () {

    var on_load = function () {
      var go2 = location.href.replace(
        /(https?:\/\/)(www\.)?amazon\.com/i,
        '$1smile.amazon.com'
      );
      location.href = go2;
    };

    $J(on_load);

  }
)();


// vim: sts=2 sw=2 ts=8 et