javascript - Firefox Webextension - TypeError: browser.contextMenus is undefined -

i refer https://developer.mozilla.org/en-us/add-ons/webextensions/api/contextmenus/onclicked. have used code in example testing in background-script.js code seems not work other webextension code.

manifest.json

{   "description": "description ...",   "manifest_version": 2,   "name": "open-my-page",   "version": "1.0",   "homepage_url": "https://github.com/",   "icons": {     "48": "icons/page-48.png"   },   "background": {     "scripts": ["background.js"]   },   "browser_action": {     "default_icon": "icons/page-32.png"   },   "content_scripts": [{     "matches": ["<all_urls>"],     "js": ["/content-script.js"]   }],   "permission": [     "activetab",     "contextmenus",     "notifications",     "tabs",     "<all_urls>"   ],   "content_security_policy": "script-src 'self' https://api.github.com; object-src 'self'; img-src 'self'" } 

background-script.js

console.log('file: background.js');  browser.contextmenus.create({   id: "click-me",   title: "click me!",   contexts: ["all"] });  browser.contextmenus.onclicked.addlistener((info, tab) => {   console.log("item " + info.menuitemid + " clicked " +               "in tab " + tab.id); }); 

content-script.js

console.log('file: content-script.js'); 

result:

typeerror: browser.contextmenus undefined 

i'm using firefox 52.0.1.

someone idea?

in manifest.json file, should permissions not permission.