Enhance Chrome Web Store: Replaces the "Available on Chrome" button, shown to other browsers, with the application download button.

Enhance Chrome Web Store 1.03.js

// ==UserScript==
// @name Enhance Chrome Web Store
// @version 1.03
// @description Replaces the "Available on Chrome" button, shown to other browsers, with the application download button.
// @namespace https://gist.github.com/2794864/
// @copyright 2012
// @author XP1
// @homepage https://github.com/XP1/
// @license Apache License, Version 2.0; http://www.apache.org/licenses/LICENSE-2.0
// @include http*://chrome.google.*/webstore/detail/*
// @include http*://*.chrome.google.*/webstore/detail/*
// ==/UserScript==

/*
 * Copyright 2012 XP1
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*jslint browser: true, vars: true, maxerr: 50, indent: 4 */
(function (console, window, ANY_TYPE) {
    "use strict";

    var userScript = {
        name: "Enhance Chrome Web Store"
    };

    var handleException = function handleException(theFunction) {
        try {
            theFunction();
        } catch (exception) {
            console.error("[" + userScript.name + "]: Exception: " + exception + "\n\nStack:\n" + exception.stack + "\n\nStacktrace:\n" + exception.stacktrace);
        }
    };

    function getApplicationId() {
        var location = window.location;
        var names = location.pathname.split("/");
        var idRegex = /[A-Za-z0-9]{32}/g;

        var i = null;
        for (i = names.length; i >= 0; i -= 1) {
            var id = names[i];
            if (idRegex.test(id)) {
                return id;
            }
        }

        throw new Error("Cannot find application ID.");
    }

    function showDownload() {
        var document = window.document;
        var location = window.location;

        var button = document.evaluate("//div[@role=\"button\"][.=\"Available on Chrome\"]", document, null, ANY_TYPE, null).iterateNext();
        document.evaluate("//[text()=\"Available on Chrome\"]", button, null, ANY_TYPE, null).iterateNext().setAttribute("id", "buttonLabel");
        var parent = button.parentNode;

        var downloadUri = "https://clients2.google.com/service/update2/crx?response=redirect&x=id%3D" + getApplicationId() + "%26uc%26lang%3Den";

        var downloadButton = button.cloneNode(true);
        downloadButton.querySelector("#buttonLabel").textContent = "Download";

        downloadButton.addEventListener("click", function downloadButtonClick() {
            location.assign(downloadUri);
        }, false);

        parent.insertBefore(downloadButton, button);
        parent.removeChild(button);
    }

    function initialize() {
        var functions = [showDownload];

        var i = null;
        var length = functions.length;
        for (i = 0; i < length; i += 1) {
            handleException(functions[i]);
        }
    }

    window.addEventListener("DOMFrameContentLoaded", initialize, false);
}(this.console, this, this.XPathResult.ANY_TYPE));