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runtime.getFrameId()

files/en-us/mozilla/add-ons/webextensions/api/runtime/getframeid/index.md

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Returns the frame ID of any window global or frame element when called from a content script or extension page, including background pages.

Syntax

js-nolint
let gettingInfo = browser.runtime.getFrameId(
  target               // object
)

Parameters

  • target
    • : A {{glossary("WindowProxy")}} or a {{glossary("browsing context")}} container Element (iframe, frame, embed, or object) for the target frame.

Return value

Returns the frame ID of the target frame, or -1 if the frame doesn't exist.

Examples

This code recursively walks descendant frames and gets parent frame IDs.

js
const parents = {};

function visit(win) {
  const frameId = browser.runtime.getFrameId(win);
  const parentId = browser.runtime.getFrameId(win.parent);
  parents[frameId] = win.parent !== win ? parentId : -1;

  try {
    const frameEl = browser.runtime.getFrameId(win.frameElement);
    browser.test.assertEq(frameId, frameEl, "frameElement id correct");
  } catch (e) {
    // Can't access a cross-origin .frameElement.
  }

  for (const frame of win.frames) {
    visit(frame);
  }
}
visit(window);

{{WebExtExamples}}

Browser compatibility

{{Compat}}