index.js

(function() {
    function checkPage(link) {
        var req = new XMLHttpRequest();
        req.onreadystatechange = function() {
            //when we get a response
            if (req.readyState === 4) {
                var possibleAnswers = /(?:answerCount">)(.*?)</.exec(req.responseText);
                var answerCount = possibleAnswers ? possibleAnswers[1] : 0;

                //if there is at least one answer
                var badgeClass;
                if (answerCount > 0) {
                    //and one was accepted
                    if (req.responseText.indexOf("vote-accepted-on") !== -1) {
                        badgeClass = "badge badge-accepted";
                    } else {
                        //and none were accepted
                        badgeClass = "badge badge-normal";
                    }
                } else {
                    //if there are no answers
                    badgeClass = "badge badge-none";
                }

                //create the badge
                var badge = document.createElement("span");
                badge.className = badgeClass;
                badge.innerText = answerCount;

                //insert the badge into the search entry
                var target = link.parentNode.nextSibling.firstChild.firstChild;
                target.insertBefore(badge, target.firstChild);
            }
        };

        req.open('GET', link.mod_href, true);
        req.send(null);
    }
    //determine if we're viewing google search as https
    var isSecureSearch = window.location.origin.match(/^https/);

    //get all of the search results
    var links = document.getElementsByTagName("a");
    for(var i = 0; i < links.length; ++i) {
        //support StackOverflow and StackExchange
        if (links[i].href.match(/http(s)?:\/\/[a-zA-Z.]*stackoverflow.com\/questions\/[0-9]*\//) ||
            links[i].href.match(/http(s)?:\/\/[a-zA-Z.]*stackexchange.com\/questions\/[0-9]*\//)) {
            var href = links[i].href;
            //use https
            if (isSecureSearch) {
                href = links[i].href.replace(/http(?!s)/, "https");
            }

            links[i].mod_href = href;
            checkPage(links[i]);
        }
    }
})();