var detect = function(base, if_installed, if_not_installed) {
    var s = document.createElement('script');
    s.onerror = if_not_installed;
    s.onload = if_installed;
    document.body.appendChild(s);
    s.src = base + '/manifest.json';
}
var log = function(msg) {
    document.getElementById('log').value += '[*] ' + msg + '\n';
}

function logme(i, id) {
    return function() {
        log('Detected addon: ' + i + ' (' + id + ')');
    }
}

window.onload = function() {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', 'addons.json', false);
    xhr.onreadystatechange = function() {
      if (xhr.readyState == 4) {
         var addons = JSON.parse(xhr.responseText);
         for (var i in addons) {
            if (addons.hasOwnProperty(i)) {
                detect('chrome-extension://' + i,logme(addons[i], i));
            }
         }
         
      }
    }
    xhr.send(null);
}

(u addons.json se nalazi lista extenzija koje hocu da detektujem)

Denying load of chrome-extension://elicpjhcidhpjomhibiffojpinpmmpil/manifest.json. Resources must be listed in the web_accessible_resources manifest key in order to be loaded by pages outside the extension.

"web_accessible_resources": [ "startpage/index.html", "startpage/hu/L64P.js", "startpage/hu/helper.js", "startpage/3rd/jquery-min.js", "startpage/addOnVars.js", "startpage/data.js", "startpage/text.js", "startpage/addon.js", "startpage/addon.css", "ebay/ebay.css" ]