This extension adds a menu item that's shown when the context menu is opened in a document. Upon click, a panel is shown, where the clicked element and its ancestor elements are displayed in a list. Upon hovering over these elements, the corresponding elements in the document are visually highlighted. When one of the list items are clicked, the element is removed from the page.

This extension demonstrates the following APIs:

• menus.create
• menus.onClicked and in particular its info.targetElementId property.
• menus.getTargetElement
• pageAction.openPopup
• pageAction.show and pageAction.hide
• tabs.executeScript

The pageAction.openPopup method requires user interaction, which is satisfied by calling the method from the menus.onClicked event.

The activeTab permission is used to unlock access to the page upon clicking the menu item, so that the info.targetElementId becomes available and tabs.executeScript can be used to run a content script in a specific frame in the tab.

The menus.getTargetElement API and info.targetElementId were introduced in Firefox 63.

In browsers that do not support this API, an extension has to register a content script that listens to the "contextmenu" event, as shown in menusGetTargetElementPolyfill.js.

This example includes the polyfill to demonstrate how one can create an extension that is compatible with browsers that do not support a new API. If you are not interested in supporting browsers that lack the browser.menus.getTargetElement API, modify the example as follows:

• Remove menusGetTargetElementPolyfill.js
• Modify popup.js and remove the entire if-block that starts with if (!browser.menus.getTargetElement) {.