Affecting Ability to add a sidebar panel has been dropped

Published: | Categories: DOM


window.sidebar.addPanel and window.sidebar.addPersistentPanel are no longer supported. These methods were a part of a Netscape-derived API which allowed Web publishers to integrate their contents as sidebar panels of the browser. They were not standardized, rarely used, and not very well supported. No other browsers have implemented these.

There is also a plan to remove window.sidebar itself in the future.

As alternatives to those API, you can create a sidebar extension or utilize the Social API.