manifest.json

{
  "manifest_version": 2,
  "name": "AutoChatter",
  "description": "This extension chats automatically on your behalf on Facebook. Just open the messages page of your Facebook and find the Autochat button. Enjoy!",
  "version": "1.0",

  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "background":{
  "scripts":["background.js"]
  },
  "icons":{
  "64":"icon.png"
  },
    "content_scripts": [
	{
	"css":["mycss.css"],
    "matches":["https://www.facebook.com/messages/t/*", "https://mbasic.facebook.com/*" ],
	"js":["jquery.min.js","myscript.js"]
  }
  ]
}