Chrome扩展程序Cookie

Question

我尝试从带有扩展名的页面获取cookie，但是当我写console.log(chrome)返回对象但cookie键不存在时 这是我的清单json

{
  "name": "Call Center",
  "manifest_version": 2,
  "version": "1.0",
  "description": "Extension For Call Center",
  "permissions": [
    "cookies",
    "*://*.youtube.com/*"
  ],
  "content_scripts": [
    {
      "matches": ["*://*.youtube.com/*"],
      "js": ["script.js"]
    }
  ],
  "web_accessible_resources": ["script.js","hello.js"]
}