Ugly hack to add "Source" and "Target" columns to Bitbucket Pull Requests list

bitbucket-pr-branches.user.js

/*jslint browser:true*/
// ==UserScript==
// @name         Bitbucket PR branches
// @namespace    http://curtisharvey.com/
// @version      0.1
// @description  Ugly hack to add "Source" and "Target" columns to Bitbucket Pull Requests list
// @author       Curtis Harvey
// @match        https://bitbucket.org/*/pull-requests/
// @match        https://bitbucket.org/*/pull-requests/?displaystatus=open
// ==/UserScript==

(function () {
    'use strict';

    var prTable = document.querySelector('#list-pullrequests table'),
        prRows = Array.prototype.slice.call(prTable.querySelectorAll('tr')),
        prDoc = document.implementation.createHTMLDocument('pr');

    prRows.forEach(function (row) {
        var source, target, insertPoint, req;
        if (row.parentNode.tagName === 'THEAD') {
            insertPoint = row.querySelector('th:nth-of-type(3)');
            source = document.createElement('th');
            target = document.createElement('th');
            source.innerHTML = 'Source';
            target.innerHTML = 'Target';
            source.style.width = '20%';
            target.style.width = '15%';
            // insert
            row.insertBefore(source, insertPoint);
            row.insertBefore(target, insertPoint);
        } else {
            insertPoint = row.querySelector('td:nth-of-type(3)');
            source = document.createElement('td');
            target = document.createElement('td');
            source.className = 'source-branch';
            target.className = 'target-branch';
            // insert
            row.insertBefore(source, insertPoint);
            row.insertBefore(target, insertPoint);
            // fetch branch details
            req = new XMLHttpRequest();
            req.addEventListener('load', function () {
                if (this.status === 200) {
                    prDoc.documentElement.innerHTML = this.responseText;
                    var branches = prDoc.querySelectorAll('dd.branch a[title]');
                    row.querySelector('.source-branch').appendChild(branches[0]);
                    row.querySelector('.target-branch').appendChild(branches[1]);
                }
            });
            req.open('get', row.querySelector('td.title a').href, true);
            req.send();
        }
    });

}());