How to use jQuery in chrome extension?

You have to add your jquery script to your chrome-extension project and to the background section of your manifest.json like this :

  "background":
    {
        "scripts": ["thirdParty/jquery-2.0.3.js", "background.js"]
    }

If you need jquery in a content_scripts, you have to add it in the manifest too:

"content_scripts": 
    [
        {
            "matches":["http://website*"],
            "js":["thirdParty/jquery.1.10.2.min.js", "script.js"],
            "css": ["css/style.css"],
            "run_at": "document_end"
        }
    ]

This is what I did.

Also, if I recall correctly, the background scripts are executed in a background window that you can open via chrome://extensions.

Its very easy just do the following:

add the following line in your manifest.json

"content_security_policy": "script-src 'self' https://ajax.googleapis.com; object-src 'self'",

Now you are free to load jQuery directly from url

  <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>

Source: google doc