content_scripts

Type	`Array`
Mandatory	No
Manifest version	2 or higher
Example	json `"content_scripts": [ { "matches": ["://.mozilla.org/*"], "js": ["borderify.js"] } ]`

Instructs the browser to load content scripts into web pages whose URL matches a given pattern.

This key is an array. Each item is an object which:

must contain a key named matches, which specifies the URL patterns to be matched in order for the scripts to be loaded;
may contain keys named js and css, which list scripts and/or stylesheets to be loaded into matching pages; and
may contain a number of other properties that control finer aspects of how and when content scripts are loaded.

Details of all the keys you can include are given in the table below.

Name	Type	Description
`all_frames`	`Boolean`	`true` Inject the scripts specified in `js` and `css` into all frames matching the specified URL requirements, even if the frame is not the topmost frame in a tab. This does not inject into child frames where only their parent matches the URL requirements and the child frame does not match the URL requirements. The URL requirements are checked for each frame independently. Note: This also applies to any tracker or ad that uses iframes, which means that enabling this could make your content script get called dozens of times on some pages. `false` Inject only into frames matching the URL requirements which are the topmost frame in a tab. Defaults to `false`.
`css`	`Array`	An array of paths, relative to `manifest.json`, referencing CSS files that will be injected into matching pages. Files are injected in the order given, and at the time specified by `run_at`. Note: Firefox resolves URLs in injected CSS files relative to the CSS file itself, rather than to the page it's injected into.
`exclude_globs`	`Array`	An array of strings containing wildcards. See Matching URL patterns below.
`exclude_matches`	`Array`	An array of match patterns. See Matching URL patterns below.
`include_globs`	`Array`	An array of strings containing wildcards. See Matching URL patterns below.
`js`	`Array`	An array of paths, relative to `manifest.json`, referencing JavaScript files that will be injected into matching pages. Files are injected in the order given. This means that, for example, if you include jQuery here followed by another content script, like this: json `"js": ["jquery.js", "my-content-script.js"]` Then, `"my-content-script.js"` can use jQuery. The files are injected after any files in `css`, and at the time specified by `run_at`.
`match_about_blank`	`Boolean`	Insert the content scripts into pages whose URL is `"about:blank"` or `"about:srcdoc"`, if the URL of the page that opened or created this page matches the patterns specified in the rest of the `content_scripts` key. This is especially useful to run scripts in empty iframes, whose URL is `"about:blank"`. To do this you should also set the `all_frames` key. For example, suppose you have a `content_scripts` key like this: json `"content_scripts": [ { "js": ["my-script.js"], "matches": ["https://example.org/"], "match_about_blank": true, "all_frames": true } ]` If the user loads `https://example.org/`, and this page embeds an empty iframe, then `"my-script.js"` will be loaded into the iframe. Note: `match_about_blank` is supported in Firefox from version 52. Note that in Firefox, content scripts won't be injected into empty iframes at `"document_start"`, even if you specify that value in `run_at`.
`match_origin_as_fallback`	`Boolean`	When `true`, code is injected into `about:`, `data:`, and `blob:` pages when their origin matches the pattern in `matches`, even if the document origin is opaque (due to the use of CSP or iframe sandbox). Match patterns in `matches` must specify a wildcard path glob. Defaults to `false`.
`matches`	`Array`	An array of match patterns. See Matching URL patterns below. This is the only mandatory key.
`run_at`	`String`	This option determines when the files specified in `css` and `js` are injected. You can supply one of three strings here, each of which identifies a state in the process of loading a document. The states directly correspond to `Document.readyState`: `"document_start"` Corresponds to `loading`. The DOM is still loading. `"document_end"` Corresponds to `interactive`. The DOM has finished loading, but resources such as scripts and images may still be loading. `"document_idle"` Corresponds to `complete`. The document and all its resources have finished loading. The default value is `"document_idle"`. In all cases, files in `js` are injected after files in `css`.
`world`	`String`	The JavaScript world the script executes in. `"ISOLATED"` The default content scripts execution environment. This environment is isolated from the page's context: while they share the same document, the global scopes and available APIs differ. `"MAIN"` The web page's execution environment. This environment is shared with the web page without isolation. Scripts in this environment don't have any access to the APIs that are only available to content scripts. Warning: Due to the lack of isolation, the web page can detect and interfere with the executed code. Do not use the `MAIN` world unless it is acceptable for web pages to read, access, or modify the logic or data that flows through the executed code. The default value is `"ISOLATED"`.

Matching URL patterns

The "content_scripts" key attaches content scripts to documents based on URL matching: if the document's URL matches the specification in the key, then the script will be attached. There are four properties inside "content_scripts" that you can use for this specification:

matches: an array of match patterns
exclude_matches: an array of match patterns
include_globs: an array of globs
exclude_globs: an array of globs

To match one of these properties, a URL must match at least one of the items in its array. For example, given a property like:

json

"matches": ["*://*.example.org/*", "*://*.example.com/*"]

Both http://example.org/ and http://example.com/ will match.

Since matches is the only mandatory key, the other three keys are used to limit further the URLs that match. To match the key as a whole, a URL must:

match the matches property
AND match the include_globs property, if present
AND NOT match the exclude_matches property, if present
AND NOT match the exclude_globs property, if present

globs

A glob is just a string that may contain wildcards.

There are two types of wildcard, and you can combine them in the same glob:

* matches zero or more characters
? matches exactly one character.

For example: "*na?i" would match "illuminati" and "annunaki", but not "sagnarelli".

Example

json

"content_scripts": [
  {
    "matches": ["*://*.mozilla.org/*"],
    "js": ["borderify.js"]
  }
]

This injects a single content script borderify.js into all pages under mozilla.org or any of its subdomains, whether served over HTTP or HTTPS.

json

  "content_scripts": [
    {
      "exclude_matches": ["*://developer.mozilla.org/*"],
      "matches": ["*://*.mozilla.org/*"],
      "js": ["jquery.js", "borderify.js"]
    }
  ]

This injects two content scripts into all pages under mozilla.org or any of its subdomains except developer.mozilla.org, whether served over HTTP or HTTPS.

The content scripts see the same view of the DOM and are injected in the order they appear in the array, so borderify.js can see global variables added by jquery.js.

Browser compatibility

BCD tables only load in the browser