chrome插件window对象chrome.extension.getBackgroundPage() underfind

Question

请问一下用uni-app开发的chrome插件（打包成h5）background.js的window对象chrome.extension.getBackgroundPage();总是underfind怎么回事

"browser_action": {

"default_icon": "logo.png",
"default_title": "AM SysInfo",
"default_popup": "dist/index.html"

},
"background":

{
    "scripts": ["background.js"],
"persistent": true

},
这是我的manifest.json配置文件
在vue里的调用
methods: {

        goTo(type) {
            this.$emit('change-page', type);
            var bg = chrome.extension.getBackgroundPage();
            console.log(bg); //Undefined
        }
    }