TypeError：无法读取undefined属性'告别'

Question

我在制作Chrome扩展程序时遇到问题。它给了我一个错误“TypeError：无法读取未定义的属性'告别'”。我是Chrome documentation做的。

后台脚本：

chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
  chrome.tabs.sendMessage(tabs[0].id, {greeting: "hello"}, function(response) {
    console.log(response.farewell);
  });
});

内容脚本：

chrome.runtime.onMessage.addListener(
function(request, sender, sendResponse) {
  console.log(sender.tab ?
              "from a content script:" + sender.tab.url :
              "from the extension");
  if (request.greeting == "hello") sendResponse({farewell: "goodbye"});
});

清单：

{
  "name": "Test",
  "version": "0.0.1",
  "description": "Test app",
  "permissions": [ "background", "tts", "storage", "webNavigation", "activeTab", "tabs" ],

  "background": { "scripts": ["my.js"] },

  "browser_action": {
    "default_popup": "my.html"
  },
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'",
  "content_security_policy": "script-src 'self' http://localhost; object-src 'self'",
  "content_scripts": [
    {
      "matches": ["http://*/*", "https://*/*"],
      "css": ["mystyles.css"],
      "js": ["autofill.js", "smart.js"]
    }
  ],
  "manifest_version": 2
}