tabs.executeScript()

Injects JavaScript code into a page.

Note:When using Manifest V3 or higher, use scripting.executeScript() to execute scripts.

You can inject code into pages whose URL can be expressed using amatch pattern. To do so, its scheme must be one of:http,https, orfile.

You must have the permission for the page's URL—either explicitly, as ahost permission—or, via theactiveTab permission. Note that some special pages do not allow this permission, including reader view, view-source, and PDF viewer pages.

You can also inject code into pages packaged with your own extension:

browser.tabs.create({ url: "/my-page.html" }).then(() => {  browser.tabs.executeScript({    code: `console.log('location:', window.location.href);`,  });});

You don't need any special permissions to do this.

Youcannot inject code 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 scripts you inject are calledcontent scripts.

This is an asynchronous function that returns aPromise.

Syntax

let executing = browser.tabs.executeScript(  tabId,                 // optional integer  details                // object)

Parameters

tabIdOptional

integer. The ID of the tab in which to run the script.

Defaults to the active tab of the current window.

details

An object describing the script to run.

It contains the following properties:

allFramesOptional

boolean. Iftrue, the code will be injected into all frames of the current page.

Iftrue andframeId is set, then it will raise an error. (frameId andallFrames are mutually exclusive.)

If it isfalse, code is only injected into the top frame.

Defaults tofalse.

codeOptional

string. Code to inject, as a text string.

Warning:Don't use this property to interpolate untrusted data into JavaScript, as this could lead to a security issue.

fileOptional

string. Path to a file containing the code to inject.

In Firefox, relative URLs not starting at the extension root are resolved relative to the current page URL.
In Chrome, these URLs are resolved relative to the extension's base URL.

To work cross-browser, you can specify the path as a relative URL, starting at the extension's root, like this:"/path/to/script.js".

frameIdOptional

integer. The frame where the code should be injected.

Defaults to0 (the top-level frame).

matchAboutBlankOptional

boolean. Iftrue, the code will be injected into embeddedabout:blank andabout:srcdoc frames if your extension has access to their parent document. The code cannot be inserted in top-levelabout: frames.

Defaults tofalse.

runAtOptional

extensionTypes.RunAt. The soonest that the code will be injected into the tab.

Defaults to"document_idle".

Return value

APromise that will resolve to an array of objects. The array's values represent the result of the script in every injected frame.

The result of the script is the last evaluated statement, which is similar to what would be output (the results, not anyconsole.log() output) if you executed the script in theWeb Console. For example, consider a script like this:

let foo = "my result";foo;

Here the results array will contain the string"my result" as an element.

The result values must bestructured cloneable (seeData cloning algorithm).

Note:The last statement may be also aPromise, but this feature is unsupported bywebextension-polyfill library.

If any error occurs, the promise will be rejected with an error message.

Examples

This example executes a one-line code snippet in the currently active tab:

function onExecuted(result) {  console.log(`We made it green`);}function onError(error) {  console.log(`Error: ${error}`);}const makeItGreen = 'document.body.style.border = "5px solid green"';const executing = browser.tabs.executeScript({  code: makeItGreen,});executing.then(onExecuted, onError);

This example executes a script from a file (packaged with the extension) called"content-script.js". The script is executed in the currently active tab. The script is executed in subframes as well as the main document:

function onExecuted(result) {  console.log(`We executed in all subframes`);}function onError(error) {  console.log(`Error: ${error}`);}const executing = browser.tabs.executeScript({  file: "/content-script.js",  allFrames: true,});executing.then(onExecuted, onError);

This example executes a script from a file (packaged with the extension) called"content-script.js". The script is executed in the tab with an ID of2:

function onExecuted(result) {  console.log(`We executed in tab 2`);}function onError(error) {  console.log(`Error: ${error}`);}const executing = browser.tabs.executeScript(2, {  file: "/content-script.js",});executing.then(onExecuted, onError);