GitHub link in Qt.io Documentation userscript

qtdoc-github-viewsource.user.js

// ==UserScript==
// @name         GitHub link in Qt.io Documentation 
// @namespace    http://grecko.fr/
// @version      0.4.1
// @description  Add a link to view the source of a class/component on Qt.io documentation pages.
// @author       GrecKo
// @match        http://doc.qt.io/*
// @match        https://doc.qt.io/*
// @match        http://doc-snapshots.qt.io/*
// @match        https://doc-snapshots.qt.io/*
// @grant        GM_xmlhttpRequest
// @updateURL    https://gist.github.com/oKcerG/a10313edf6187f43f57e/raw/qtdoc-github-viewsource.user.js
// ==/UserScript==

var head = document.querySelector('head');
var children = head.childNodes;
for (var i=0, len=children.length; i<len; i++) {
    if (children[i].nodeType == Node.COMMENT_NODE) {
        comment = children[i];
        var filename = comment.textContent.trim();
        if (filename.endsWith('.qdoc'))
            return;
        var excludedRepos=['qt','qt-mobility']; 
        var searchUrl = 'https://api.github.com/search/code?q=user:qtproject';
        for (var i = 0; i < excludedRepos.length; ++i)
            searchUrl += '+-repo:qtproject/'+excludedRepos[i];
        searchUrl += '+filename:'+filename;
        GM_xmlhttpRequest ({
            method: 'get',
            url: searchUrl,
            onload: searchListener
        });
        return;
    }
}

function searchListener (r) {
    var response = JSON.parse(r.responseText);
    var sourceUrl = response.items[0].html_url;
    var sourceLink = document.createElement('a');
    sourceLink.setAttribute('href', sourceUrl);
    sourceLink.textContent = 'View the source on GitHub';
    var branch = sourceLink.pathname.split('/')[4];
    //sourceLink.pathname = sourceLink.pathname.replace(branch, 'dev');
    var title = document.querySelector('.title');
    var parent = title.parentNode;
    var subtitle = document.querySelector('.subtitle');
    var nextSibling = title.nextSibling;
    parent.insertBefore(sourceLink, nextSibling);
    parent.insertBefore(document.createElement('br'), nextSibling);
    if (sourceUrl.endsWith('.cpp')) {
        var headerUrl =  sourceUrl.replace('.cpp', '.h');
        var headerLink = document.createElement('a');
        headerLink.setAttribute('href', headerUrl);
        headerLink.textContent = 'View the header on GitHub';
        GM_xmlhttpRequest ({
            method: 'head',
            url: headerUrl,
            onload: function (response) {
                if (response.status === 200) {
                    parent.insertBefore(headerLink, nextSibling);
                    parent.insertBefore(document.createElement('br'), nextSibling);
                }
            }
        });

        var privateHeaderUrl = sourceUrl.replace('.cpp', '_p.h');
        var privateHeaderLink = document.createElement('a');
        privateHeaderLink.setAttribute('href', privateHeaderUrl);
        privateHeaderLink.textContent = 'View the private header on GitHub';
        GM_xmlhttpRequest ({
            method: 'head',
            url: privateHeaderUrl,
            onload: function (response) {
                if (response.status === 200) {
                    parent.insertBefore(privateHeaderLink, nextSibling);
                    parent.insertBefore(document.createElement('br'), nextSibling);
                    nextSibling = privateHeaderLink;
                }
            }
        });
    }
}