github_add_branch_links_userscript.js

// ==UserScript==
// @name       Add Branch Links
// @namespace  http://www.github.com/
// @version    0.1
// @description  Add extra links to branches page
// @match      https://github.com/*/branches*
// @copyright  2014, Kevin Trotter
// ==/UserScript==

$(function () {
    $("a.branch-name").each(function (i, o) {
        var $this = $(o),
            org = $('.author span').text(),
            repo = $('.js-current-repository').text(),
            defaultBranch = $(".branch-group-name:first").parent().parent().find(".branch-name").text(),
            branch = $this.text(),
            $commitsUrl = $("<span>&nbsp;<a href='/" + org + "/" + repo + "/commits/" + branch + "'>commits</a></span>"),
            $compareUrl = $("<span>&nbsp;&middot;&nbsp;<a href='/" + org + "/" + repo + "/compare/%branch%..." + branch + "'>compare&nbsp;to...</a></span>"),
            $beforeText = $this.parent().find(".branch-meta");

        if (defaultBranch != branch) {
            $compareUrl.insertAfter($beforeText);
        }
        $commitsUrl.insertAfter($beforeText);
        $compareUrl.find("a").click(function () {
            var branch = prompt("Which branch would you like to compare to?");
            if (!branch) {
                branch = defaultBranch;
            }
            var href = $(this).attr("href");
            $(this).attr("href", href.replace("%branch%", branch));
        })
    });
})