tabs.insertCSS()

Injects CSS into a page.

To use this API you must have the permission for the page's URL, either explicitly as a host permission, or using the activeTab permission.

You can only inject CSS into pages whose URL can be expressed using a match pattern: meaning, its scheme must be one of "http", "https", "file", "ftp". This means that you can't inject CSS into any of the browser's built-in pages, such as about:debugging, about:addons, or the page that opens when you open a new empty tab.

The inserted CSS may be removed again by calling tabs.removeCSS().

Syntax

chrome.tabs.insertCSS(
  tabId,           // optional integer
  details,         // extensionTypes.InjectDetails
  function() {...} // optional function
)

This API is also available as browser.tabs.insertCSS() in a version that returns a promise.

Parameters

tabId Optional

integer. The ID of the tab in which to insert the CSS. Defaults to the active tab of the current window.

details

extensionTypes.InjectDetails. Describes the CSS to insert. This contains the following properties:

allFramesOptional

boolean. If true, the CSS will be injected into all frames of the current page. If it is false, CSS is only injected into the top frame. Defaults to false.

codeOptional

string. Code to inject, as a text string.

fileOptional

string. Path to a file containing the code to inject. In Firefox, relative URLs are resolved relative to the current page URL. In Chrome, these URLs are resolved relative to the add-on's base URL. To work cross-browser, you can specify the path as an absolute URL, starting at the add-on's root, like this: "/path/to/stylesheet.css".

frameIdOptional

integer. The frame where the CSS should be injected. Defaults to 0 (the top-level frame).

matchAboutBlankOptional

boolean. If true, the code will be injected into embedded "about:blank" and "about:srcdoc" frames if your add-on has access to their parent document. The code cannot be inserted in top-level about: frames. Defaults to false.

runAtOptional

extensionTypes.RunAt. The soonest that the code will be injected into the tab. Defaults to "document_idle".

callback Optional

function. Called, with no arguments, when all the CSS has been inserted.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Compatibility notes

Firefox

• 'matchAboutBlank' is not supported.

Examples

This example inserts into the currently active tab CSS which is taken from a string.

var css = "body { border: 20px dotted pink; }";

chrome.browserAction.onClicked.addListener(function() {
  chrome.tabs.insertCSS({code: css});
});

This example inserts into the active tab CSS which is loaded from a file which is included as part of the extension.

chrome.browserAction.onClicked.addListener(function() {
  chrome.tabs.insertCSS({file: "content-style.css"});
});

This more intricate call to tabs.insertCSS() injects the CSS loaded from a bundled file into the tab whose ID is 5. In addition, the CSS is injected not only into the tab's primary document, but into every frame within the tab as well.

When all of the CSS injection is completed, the provided onExecuted() function is called.

function onExecuted() {
  console.log("finished");
}

chrome.browserAction.onClicked.addListener(function() {

  chrome.tabs.insertCSS(
    5, {
    file: "content-style.css",
    allFrames: true
  }, onExecuted);

});

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