Threadless Infinite Scroll

Infinite scroll for threadless.com
Versión del día 9/7/2017. Echa un vistazo a la versión más reciente.
Pregunta tus dudas, ponle nota o notifica una posible infracción de las normas.
Ajuste de línea
// ==UserScript==
// @name         Threadless Infinite Scroll
// @namespace    https://github.com/arieljannai
// @version      0.2
// @description  Infinite scroll for threadless.com
// @author       Ariel Jannai
// @match        *://www.threadless.com/*
// @icon         https://www.threadless.com/favicon.ico
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    var infiniteLoadingGif = "<div class='infinite-loading' style='text-align:center; margin:0 auto; width:50%'><img src='https://i.imgur.com/NH1zQtD.gif'></img></div>";

    function isScrolledIntoView(elem) {
        var docViewTop = $(window).scrollTop();
        var docViewBottom = docViewTop + $(window).height();

        var elemTop = $(elem).offset().top;
        var elemBottom = elemTop + $(elem).height();

        return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
    }

    var back_top = $('.back_top');
    var pathname = document.location.pathname;
    var pageMatch = pathname.match(/page,(\d+)/);
    var currPage = pageMatch ? pageMatch[1] : 1;
    var requestNext = true;
    pathname = pathname.replace(/\/page,\d+/, '') + '/page,' + currPage;

    function getPagePath(pageNum) {
        return pathname.replace(/page,\d+/, 'page,' + pageNum);
    }

    function appendPageItems(pageNum) {
        console.log('loading page: ', pageNum);
        var msg = '';
        $('<div>').load(getPagePath(pageNum) + ' #catalog_products', function(html, status) {
            console.log('status: ', status);
            if (status !== 'success') {
                requestNext = false;
                msg = 'Oops. There was an error while loading the next page items (page ' + pageNum + ').';
                console.error(msg);
                $('<div style="text-align:center; color:red">' + msg + '</div>').insertAfter('#catalog_products');
                $('div .catalog_browsing').show();
            } else if (html.indexOf('class="no-results"') > -1) {
                console.log('not loaded: ', pageNum);
                msg = 'No more items :(';
                console.log(msg);
                $('<div style="text-align:center">' + msg + '</div>').insertAfter('#catalog_products');
            } else {
                $('#catalog_products').append($(this));
                requestNext = true;
                console.log('loaded:', pageNum);
            }

            $('.infinite-loading').hide();
        });
    }

    $('div .catalog_browsing').hide();
    $(infiniteLoadingGif).insertBefore('div .catalog_browsing');
    $('.infinite-loading').hide();

    $(window).scroll(function() {
        if (requestNext && isScrolledIntoView(back_top)) {
            $('.infinite-loading').show();
            requestNext = false;
            appendPageItems(++currPage);
        }
    });
})();