Adapted code to JSON change

eventPage.js

 }
 
 function getCurrentTabUrl(callback) {
-  // Query filter to be passed to chrome.tabs.query - see
-  // https://developer.chrome.com/extensions/tabs#method-query
   var queryInfo = {
     active: true,
     currentWindow: true
   };
 
   chrome.tabs.query(queryInfo, function(tabs) {
-    // chrome.tabs.query invokes the callback with a list of tabs that match the
-    // query. When the popup is opened, there is certainly a window and at least
-    // one tab, so we can safely assume that |tabs| is a non-empty array.
-    // A window can only have one active tab at a time, so the array consists of
-    // exactly one tab.
     var tab = tabs[0];
 
-    // A tab is a plain object that provides information about the tab.
-    // See https://developer.chrome.com/extensions/tabs#type-Tab
     var url = tab.url;
 
-    // tab.url is only available if the "activeTab" permission is declared.
-    // If you want to see the URL of other tabs (e.g. after removing active:true
-    // from |queryInfo|), then the "tabs" permission is required to see their
-    // "url" properties.
     console.assert(typeof url == 'string', 'tab.url should be a string');
 
     callback(url);
   });
-
-  // Most methods of the Chrome extension APIs are asynchronous. This means that
-  // you CANNOT do something like this:
-  //
-  // var url;
-  // chrome.tabs.query(queryInfo, function(tabs) {
-  //   url = tabs[0].url;
-  // });
-  // alert(url); // Shows "undefined", because chrome.tabs.query is async.
 }
 
 function updateTab() {
     getCurrentTabUrl(function(url) {
         chrome.storage.local.get("sites", function(sites){
             sites = sites.sites
-            if(url.match(/:\/\/([^\/]+)\//)[1] in sites) {
+            domain = url.match(/:\/\/(www\.)?([^\/]+)\//).slice(-1)[0]
+            if(domain in sites) {
                 chrome.browserAction.setIcon({path: 'icon-red.png'})
             }
             else {

popup.js

 getCurrentTabUrl(function(url) {
     chrome.storage.local.get("sites", function(sites){
         sites = sites.sites
-        domain = url.match(/:\/\/([^\/]+)\//)[1]
+        domain = url.match(/:\/\/(www\.)?([^\/]+)\//).slice(-1)[0]
         if(domain in sites) {
             proxies = sites[domain]
             $("#mirror").css("display", "block")