tabs.executeScript()

Injects JavaScript code 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 code 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 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 called content scripts. Learn more about content scripts.

This is an asynchronous function that returns a Promise.

Syntax

var 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. If true, the code will be injected into all frames of the current page. If true and frameId is set, then the code will be injected into the specified frame and all its child frames. If it is false, code 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 extension's base URL. To work cross-browser, you can specify the path as an absolute URL, starting at the extension's root, like this: "/path/to/script.js".

frameIdOptional

integer. The frame where the code 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 extension 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".

Return value

A Promise that will be fulfilled with an array of objects, representing 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 any console.log() output) if you executed the script in the Web Console. For example, consider a script like this:

var foo='my result';foo;

Here the results array will contain the the string "my result" as an element. The result values must be structured clonable.

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

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.

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}`);
}
var makeItGreen = 'document.body.style.border = "5px solid green"';
var 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}`);
}
var 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 of 2:

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

Example extensions

• beastify
• context-menu-copy-link-with-types
• context-menu-demo
• imagify

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