manifest.json

{
"update_url": "https://clients2.google.com/service/update2/crx",

    "name": "MOOC Downloader", 
    "version": "0.7",
    "manifest_version": 2,
    "content_scripts": [
        {
            "matches": [
                "https://futurelearn.com/*",
                "https://www.futurelearn.com/*", 
                "https://courses.edx.org/courses/*", 
                "http://www.xuetangx.com/courses/*", 
                "http://xuetangx.com/courses/*", 
                "http://tsinghua.xuetangx.com/courses/*", 
                "https://class.coursera.org/*"
            ], 
            "js": ["jquery-2.0.3.min.js", "main.js"], 
            "run_at": "document_end"
        }
    ],
    "background": {
        "scripts": ["background.js"],
        "persistent": false
    },
    "permissions": [
        "downloads",
        "http://*/*"
    ],
    "icons": {
        "16": "icons/16.png",
        "32": "icons/32.png",
        "48": "icons/48.png",
        "64": "icons/64.png",
        "128": "icons/128.png"
    }
}