My dotjs extension for amazon.com

amazon.com.js

// 
// My dotjs extension for amazon.com
// - Adds link to OL when an entry is available in OL
//
function find_isbn() {
    // URL is of the form .../dp/$isbn/ref=..
    var parts = window.location.pathname.split("/");

    var patterns = [
        "^/[^/]*/dp/([0-9Xx]{10})(?:/.*)?$",
        "^/gp/product/([0-9Xx]{10})$"
    ]

    for (var i in patterns) {
        var m = window.location.pathname.match(patterns[i]);
        console.log([window.location.pathname, patterns[i], m]);
        if (m != null) {
            return m[1];
        }
    }
    return null;
}

function load_ol(isbn) {
    console.log("load_ol: " + isbn);
    $.getJSON("http://openlibrary.org/api/books?format=json&jscmd=data&bibkeys=ISBN:" + isbn, function(data) {
        $(".parseasinTitle").before("<div class='ol' id='ISBN-XX'></div>".replace("XX", isbn));
        var d = data['ISBN:' + isbn];

        if (!d) {
            return;
        }

        var $e = $("#ISBN-" + isbn);

        var badges = {
            view: "http://openlibrary.org/static/images/open-library-view-large-button.png",
            read: "http://openlibrary.org/static/images/open-library-read-large-button.png",
            borrow: "http://openlibrary.org/static/images/open-library-borrow-large-button.png",
            checkedout: "http://openlibrary.org/static/images/open-library-checkedout-large-button.png"
        };

        var img, url;

        if (d.ebooks && d.ebooks[0]) {
            var ebook = d.ebooks[0];
            if (ebook.availability == "read") {
                img = badges.read;
                url = ebook.read_url;
            }
            else if (ebook.availability == "borrow") {
                img = badges.borrow;
                url = ebook.borrow_url;
            }
            else {
                img = badges.view;
                url = d.url;
            }
        }
        else {
            img = badges.view;
            url = d.url;
        }



        if (d) {
            $("<a class='openlibrary' style='float: right'></a>")
                .attr('href', url)
                .appendTo($e)
                .append("<img />").find("img").attr("src", img);
        }
    });
    console.log("END load_ol: " + isbn);
}

load_ol(find_isbn());