window.sidebar and window.external.AddSearchProvider() have been deprecated

Published: | Categories: DOM


The non-standard, Netscape-derived window.sidebar object, an alias of window.external, is now officially considered deprecated and will be removed in the future. The object is no longer available on the Nightly channel as of Firefox 65. Web developers must stop using it for browser detection.

The IE-derived window.external object will remain, but the AddSearchProvider and IsSearchProviderInstalled methods on it will be no-op, simply returning undefined, according to the latest HTML spec. This change has also been made to Firefox 65 Nightly. While AddSearchProvider could be used to add an OpenSearch plug-in to the browser, IsSearchProviderInstalled was always returning 0 on Firefox.

There is no plan to remove the auto-discovery of search plug-ins via <link rel="search">, which is a recommended way to provide an OpenSearch plug-in on a website.

Update: Firefox 66 Nightly has re-enabled window.sidebar and these methods as Firefox developers are thinking about a plan to migrate the search provider installer.