chrome.scripting (original) (raw)

Description

Use the chrome.scripting API to execute script in different contexts.

Permissions

scripting

Availability

Manifest

To use the chrome.scripting API, declare the "scripting" permission in the manifest plus the host permissions for the pages to inject scripts into. Use the "host_permissions" key or the "activeTab" permission, which grants temporary host permissions. The following example uses the activeTab permission.

{
  "name": "Scripting Extension",
  "manifest_version": 3,
  "permissions": ["scripting", "activeTab"],
  ...
}

Concepts and usage

You can use the chrome.scripting API to inject JavaScript and CSS into websites. This is similar to what you can do with content scripts. But by using the chrome.scripting namespace, extensions can make decisions at runtime.

Injection targets

You can use the target parameter to specify a target to inject JavaScript or CSS into.

The only required field is tabId. By default, an injection will run in the main frame of the specified tab.

function getTabId() { ... }

chrome.scripting
    .executeScript({
      target : {tabId : getTabId()},
      files : [ "script.js" ],
    })
    .then(() => console.log("script injected"));

To run in all frames of the specified tab, you can set the allFrames boolean to true.

function getTabId() { ... }

chrome.scripting
    .executeScript({
      target : {tabId : getTabId(), allFrames : true},
      files : [ "script.js" ],
    })
    .then(() => console.log("script injected in all frames"));

You can also inject into specific frames of a tab by specifying individual frame IDs. For more information on frame IDs, see the chrome.webNavigationAPI.

function getTabId() { ... }

chrome.scripting
    .executeScript({
      target : {tabId : getTabId(), frameIds : [ frameId1, frameId2 ]},
      files : [ "script.js" ],
    })
    .then(() => console.log("script injected on target frames"));

Injected code

Extensions can specify the code to be injected either via an external file or a runtime variable.

Files

Files are specified as strings that are paths relative to the extension's root directory. The following code will inject the file script.js into the main frame of the tab.

function getTabId() { ... }

chrome.scripting
    .executeScript({
      target : {tabId : getTabId()},
      files : [ "script.js" ],
    })
    .then(() => console.log("injected script file"));

Runtime functions

When injecting JavaScript with scripting.executeScript(), you can specify a function to be executed instead of a file. This function should be a function variable available to the current extension context.

function getTabId() { ... }
function getTitle() { return document.title; }

chrome.scripting
    .executeScript({
      target : {tabId : getTabId()},
      func : getTitle,
    })
    .then(() => console.log("injected a function"));

function getTabId() { ... }
function getUserColor() { ... }

function changeBackgroundColor() {
  document.body.style.backgroundColor = getUserColor();
}

chrome.scripting
    .executeScript({
      target : {tabId : getTabId()},
      func : changeBackgroundColor,
    })
    .then(() => console.log("injected a function"));

You can work around this by using the args property:

function getTabId() { ... }
function getUserColor() { ... }
function changeBackgroundColor(backgroundColor) {
  document.body.style.backgroundColor = backgroundColor;
}

chrome.scripting
    .executeScript({
      target : {tabId : getTabId()},
      func : changeBackgroundColor,
      args : [ getUserColor() ],
    })
    .then(() => console.log("injected a function"));

Runtime strings

If injecting CSS within a page, you can also specify a string to be used in thecss property. This option is only available for scripting.insertCSS(); you can't execute a string using scripting.executeScript().

function getTabId() { ... }
const css = "body { background-color: red; }";

chrome.scripting
    .insertCSS({
      target : {tabId : getTabId()},
      css : css,
    })
    .then(() => console.log("CSS injected"));

Handle the results

The results of executing JavaScript are passed to the extension. A single result is included per-frame. The main frame is guaranteed to be the first index in the resulting array; all other frames are in a non-deterministic order.

function getTabId() { ... }
function getTitle() { return document.title; }

chrome.scripting
    .executeScript({
      target : {tabId : getTabId(), allFrames : true},
      func : getTitle,
    })
    .then(injectionResults => {
      for (const {frameId, result} of injectionResults) {
        console.log(`Frame ${frameId} result:`, result);
      }
    });

scripting.insertCSS() does not return any results.

Promises

If the resulting value of the script execution is a promise, Chrome will wait for the promise to settle and return the resulting value.

function getTabId() { ... }
async function addIframe() {
  const iframe = document.createElement("iframe");
  const loadComplete =
      new Promise(resolve => iframe.addEventListener("load", resolve));
  iframe.src = "https://example.com";
  document.body.appendChild(iframe);
  await loadComplete;
  return iframe.contentWindow.document.title;
}

chrome.scripting
    .executeScript({
      target : {tabId : getTabId(), allFrames : true},
      func : addIframe,
    })
    .then(injectionResults => {
      for (const frameResult of injectionResults) {
        const {frameId, result} = frameResult;
        console.log(`Frame ${frameId} result:`, result);
      }
    });

Examples

Unregister all dynamic content scripts

The following snippet contains a function that unregisters all dynamic content scripts the extension has previously registered.

async function unregisterAllDynamicContentScripts() {
  try {
    const scripts = await chrome.scripting.getRegisteredContentScripts();
    const scriptIds = scripts.map(script => script.id);
    return chrome.scripting.unregisterContentScripts({ ids: scriptIds });
  } catch (error) {
    const message = [
      "An unexpected error occurred while",
      "unregistering dynamic content scripts.",
    ].join(" ");
    throw new Error(message, {cause : error});
  }
}

To try the chrome.scripting API, install the scripting sample from the Chrome extension samplesrepository.

Types

ContentScriptFilter

Properties

• If specified, getRegisteredContentScripts will only return scripts with an id specified in this list.

CSSInjection

Properties

• A string containing the CSS to inject. Exactly one of files and css must be specified.
• The path of the CSS files to inject, relative to the extension's root directory. Exactly one of files and css must be specified.
• origin
  StyleOrigin optional
  The style origin for the injection. Defaults to 'AUTHOR'.
• Details specifying the target into which to insert the CSS.

ExecutionWorld

The JavaScript world for a script to execute within.

Enum

"ISOLATED"
Specifies the isolated world, which is the execution environment unique to this extension.

"MAIN"
Specifies the main world of the DOM, which is the execution environment shared with the host page's JavaScript.

InjectionResult

Properties

• The document associated with the injection.
• The frame associated with the injection.
• The result of the script execution.

InjectionTarget

Properties

• allFrames
  boolean optional
  Whether the script should inject into all frames within the tab. Defaults to false. This must not be true if frameIds is specified.
• documentIds
  string[] optional
  The IDs of specific documentIds to inject into. This must not be set if frameIds is set.
• frameIds
  number[] optional
  The IDs of specific frames to inject into.
• The ID of the tab into which to inject.

RegisteredContentScript

Properties

• allFrames
  boolean optional
  If specified true, it will inject into all frames, even if the frame is not the top-most frame in the tab. Each frame is checked independently for URL requirements; it will not inject into child frames if the URL requirements are not met. Defaults to false, meaning that only the top frame is matched.
• The list of CSS files to be injected into matching pages. These are injected in the order they appear in this array, before any DOM is constructed or displayed for the page.
• excludeMatches
  string[] optional
  Excludes pages that this content script would otherwise be injected into. See Match Patterns for more details on the syntax of these strings.
• The id of the content script, specified in the API call. Must not start with a '_' as it's reserved as a prefix for generated script IDs.
• The list of JavaScript files to be injected into matching pages. These are injected in the order they appear in this array.
• matchOriginAsFallback
  boolean optional
  Indicates whether the script can be injected into frames where the URL contains an unsupported scheme; specifically: about:, data:, blob:, or filesystem:. In these cases, the URL's origin is checked to determine if the script should be injected. If the origin is null (as is the case for data: URLs) then the used origin is either the frame that created the current frame or the frame that initiated the navigation to this frame. Note that this may not be the parent frame.
• matches
  string[] optional
  Specifies which pages this content script will be injected into. See Match Patterns for more details on the syntax of these strings. Must be specified for registerContentScripts.
• persistAcrossSessions
  boolean optional
  Specifies if this content script will persist into future sessions. The default is true.
• Specifies when JavaScript files are injected into the web page. The preferred and default value is document_idle.
• world
  ExecutionWorld optional
  The JavaScript "world" to run the script in. Defaults to ISOLATED.

ScriptInjection

Properties

• The arguments to pass to the provided function. This is only valid if the func parameter is specified. These arguments must be JSON-serializable.
• The path of the JS or CSS files to inject, relative to the extension's root directory. Exactly one of files or func must be specified.
• injectImmediately
  boolean optional
  Whether the injection should be triggered in the target as soon as possible. Note that this is not a guarantee that injection will occur prior to page load, as the page may have already loaded by the time the script reaches the target.
• Details specifying the target into which to inject the script.
• world
  ExecutionWorld optional
  The JavaScript "world" to run the script in. Defaults to ISOLATED.
• A JavaScript function to inject. This function will be serialized, and then deserialized for injection. This means that any bound parameters and execution context will be lost. Exactly one of files or func must be specified.
  The func function looks like:
  () => {...}

StyleOrigin

The origin for a style change. See style origins for more info.

Enum

Methods

executeScript()

chrome.scripting.executeScript(
  injection: ScriptInjection,
): Promise<InjectionResult[]>

Injects a script into a target context. By default, the script will be run at document_idle, or immediately if the page has already loaded. If the injectImmediately property is set, the script will inject without waiting, even if the page has not finished loading. If the script evaluates to a promise, the browser will wait for the promise to settle and return the resulting value.

Parameters

• The details of the script which to inject.

Returns

• Promise<InjectionResult[]>

getRegisteredContentScripts()

chrome.scripting.getRegisteredContentScripts(
  filter?: ContentScriptFilter,
): Promise<RegisteredContentScript[]>

Returns all dynamically registered content scripts for this extension that match the given filter.

Parameters

• filter
  ContentScriptFilter optional
  An object to filter the extension's dynamically registered scripts.

Returns

insertCSS()

chrome.scripting.insertCSS(
  injection: CSSInjection,
): Promise

Inserts a CSS stylesheet into a target context. If multiple frames are specified, unsuccessful injections are ignored.

Parameters

• The details of the styles to insert.

Returns

registerContentScripts()

chrome.scripting.registerContentScripts(
  scripts: RegisteredContentScript[],
): Promise

Registers one or more content scripts for this extension.

Parameters

• Contains a list of scripts to be registered. If there are errors during script parsing/file validation, or if the IDs specified already exist, then no scripts are registered.

Returns

removeCSS()

chrome.scripting.removeCSS(
  injection: CSSInjection,
): Promise

Removes a CSS stylesheet that was previously inserted by this extension from a target context.

Parameters

• The details of the styles to remove. Note that the css, files, and origin properties must exactly match the stylesheet inserted through insertCSS. Attempting to remove a non-existent stylesheet is a no-op.

Returns

unregisterContentScripts()

chrome.scripting.unregisterContentScripts(
  filter?: ContentScriptFilter,
): Promise

Unregisters content scripts for this extension.

Parameters

• filter
  ContentScriptFilter optional
  If specified, only unregisters dynamic content scripts which match the filter. Otherwise, all of the extension's dynamic content scripts are unregistered.

Returns

updateContentScripts()

chrome.scripting.updateContentScripts(
  scripts: RegisteredContentScript[],
): Promise

Updates one or more content scripts for this extension.

Parameters

• Contains a list of scripts to be updated. A property is only updated for the existing script if it is specified in this object. If there are errors during script parsing/file validation, or if the IDs specified do not correspond to a fully registered script, then no scripts are updated.

Returns