Replaced onRequest and sendRequest with onMessage and sendMessage. Changed background page persistence to true. Made separate popup.js file. Made popup wider. Works in latest Chrome now.

Author: bagofarms

bg.js

@@ -4,7 +4,7 @@ var selectedItem = null;
 var selectedId = null;
 
 function updateItem(tabId) {
-    chrome.tabs.sendRequest(tabId, {}, function(item) {
+    chrome.tabs.sendMessage(tabId, {}, function(item) {
         items[tabId] = item;
         if (!item) {
           chrome.pageAction.hide(tabId);

cs.js

@@ -1,5 +1,5 @@
 if (window == top) {
-  chrome.extension.onRequest.addListener(function(req, sender, senderResponse) {
+  chrome.extension.onMessage.addListener(function(req, sender, senderResponse) {
     senderResponse(findItemID());
   });
 }

manifest.json

@@ -5,7 +5,7 @@
   "description": "Generate an Amazon affiliate link with one click",
   "background": {
     "scripts": ["jq.min.js","bg.js"],
-    "persistent": false
+    "persistent": true
   },
   "icons": {
     "16": "images/icon_16.png",

popup.html

@@ -3,7 +3,7 @@
         <title>Popup</title>
         <style>
             body {
-                width: 300px;
+                width: 400px;
             }
 
             label {
@@ -14,7 +14,7 @@
 
             input[type='text'] {
                 display: inline-block;
-                width: 200px;
+                width: 300px;
             }
         </style>
     </head>
@@ -24,19 +24,5 @@
     </body>
     <script src="jq.min.js"></script>
     <script src="jquery.url.js"></script>
-    <script>
-        window.onload = function() {
-            var item = chrome.extension.getBackgroundPage().selectedItem;
-            if (item) {
-                chrome.tabs.getSelected(null, function(tab) {
-                    var tablink = tab.url,
-                        host = $.url(tablink).attr('host'),
-                        link = 'http://' + host + '/dp/' + item + '/?tag='
-                                + localStorage['trackId'];
-                    console.log(link);
-                    $('#txt').val(link);
-                });
-            }
-        }
-    </script>
+    <script src="popup.js"></script>
 </html>

popup.js

@@ -0,0 +1,13 @@
+window.onload = function() {
+    var item = chrome.extension.getBackgroundPage().selectedItem;
+    if (item) {
+        chrome.tabs.getSelected(null, function(tab) {
+            var tablink = tab.url,
+                host = $.url(tablink).attr('host'),
+                link = 'http://' + host + '/dp/' + item + '/?tag='
+                        + localStorage['trackId'];
+            console.log(link);
+            $('#txt').val(link);
+        });
+    }
+}