gistfile1.txt

// ==UserScript==
// @run-at document-start
// @id             Aliexpress URL Cleaner
// @name           Aliexpress URL Cleaner
// @namespace
// @description    Clean aliexpress item URL
// @include        http://www.aliexpress.com/item/*
// @include        https://www.aliexpress.com/item/*
// @include        http://www.aliexpress.com/store/product/*
// @include        https://www.aliexpress.com/store/product/*
// @version        1.1
// ==/UserScript==

(function() {
    'use strict';

    var p1 = document.URL.match(/https?:\/\/(|www).aliexpress.com\/(?:item|store\/product)\//g);
    var p2 = document.URL.match(/\/[0-9_]+[.]html(?=$|[?])/g);
    if (p1 && p2 && p1+p2 != document.URL) history.replaceState(null, '', p1+p2);
})();