Question

Here is my manifest:

{
  "name": "test.",
  "version": "1.0",
  "permissions": [
    "tabs", "http://*/*", "https://*/*"
  ],
   "content_scripts": [
  {      
  "js": ["jquery.js"]
  }
 ],
  "browser_action": {
      "default_title": "Set this page's color.",
      "default_icon": "icon.png",
     "default_popup": "popup.html"
  },
  "manifest_version": 2
}

and my popup.js

function click(e) {
  chrome.tabs.executeScript(null,
  {code:"$('img').css('display','none');
  window.close();
}

document.addEventListener('DOMContentLoaded', function () {
...
  }
});

But for some reason
i get the error

Uncaught ReferenceError: $ is not defined

Why?

Answer 1

Problem in your code

• There are not match Patterns in your manifest, so jQuery did not run\injected in any places, so $ or jQuery keywords are undefined.

Solution

Modify your manifest to include URL where jQuery is to be injected(Do not forget to declare permission(s) for the URL’s.

"content_scripts": [
    {
      "matches": ["http://www.google.com/*"]
      "js": ["jquery.js", "myscript.js"]
    }
  ],

The above injects jQuery in a Google Page, use <all_urls> to inject in all websites.

References

• Content Scripts
• Match Patterns