Chrome 扩展警报创建“未定义”

Question

I'm creating a plugin for google chrome extensions and for the life of me cannot figure out this error.

Uncaught TypeError: Cannot read property 'create' of undefined(anonymous function)

The strange thing is the alarm works fine! My manifest has the proper permissions:

  "permissions": ["activeTab","storage","alarms"]

And my code in background.js which corresponds to the error looks like so:

var alarmName = "test";

chrome.alarms.create(alarmName, {
  delayInMinutes: 0,
  periodInMinutes: 1
});

chrome.alarms.onAlarm.addListener(function(alarmName) {
  alert("Here");
});

Any ideas why I'm getting this issue? Thanks

EDIT: Here's my whole manifest.

{
"manifest_version": 2,

"name": "Test App",
"options_page": "options.html",
"description": "Amazing new test app!",
"version": "1.0",

"icons": { "16": "icon16.png",
       "48": "icon48.png",
      "128": "icon128.png" },

"browser_action": {
"default_icon": "icon.png",
"default_popup": "popup.html"
},

"content_scripts": [ {
"js": [ "jquery.min.js", "jquery.js", "background.js" ],
"matches": [ "http://*/*", "https://*/*"]
}],
"background": {
"scripts": ["jquery.min.js", "jquery.js", "background.js"],
"persistent":true
},
"web_accessible_resources": ["src/options/options.html"],
"permissions": [
"activeTab","storage","alarms"]
}

Answer 1

"content_scripts": [ {
  "js": [ "jquery.min.js", "jquery.js", "background.js" ],
  "matches": [ "http://*/*", "https://*/*"]
}],

First, a piece of advice.

Never call your content scripts background.js

This is a huge source of confusion, since it's not the same as background scripts.

And it's also the reason it does not work: content scripts don't have access to most Chrome APIs :

However, content scripts have some limitations. They cannot:

Use chrome.* APIs, with the exception of:

• extension ( getURL , inIncognitoContext , lastError , onRequest , sendRequest )
• i18n
• runtime ( connect , getManifest , getURL , id , onConnect , onMessage , sendMessage )
• storage

You'll need to message your (real) background script to do this for you. Don't reuse code like that, since it's a completely different context.

The alarm "works fine" since you also have this code in the background page, where it works properly.

You can observe this by opening chrome://extensions and clicking the "background page" link to inspect it. You seem to be looking in the current page's console and seeing the content script's output.

Take a moment to read the Architecture Overview .