stylesheet/utils

We are planning to deprecate the use by Firefox add-ons of the techniques described in this document.

Don't use these techniques to develop new add-ons. Use WebExtensions instead.

If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions instead.

Add-ons developed using these techniques might not work with multiprocess Firefox (e10s), which is already the default in Firefox Nightly and Firefox Developer Edition, and will soon be the default in Beta and Release versions of Firefox. We have documentation on making your add-ons multiprocess-compatible, but it will be more future-proof for you to migrate to WebExtensions.

A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.

Experimental

Helper functions for working with stylesheets.

Globals

Functions

loadSheet(window, uri, type)

Synchronously loads a style sheet from uri and adds it to the list of additional style sheets of the document. The sheets added takes effect immediately, and only on the document of the window given.

Parameters

window : nsIDOMWindow

uri : string,
nsIURI}

type : string
The type of the sheet. It accepts the following values: "agent", "user" and "author". If not provided, the default value is "author".

removeSheet(window, uri, type)

Remove the document style sheet at sheetURI from the list of additional style sheets of the document. The removal takes effect immediately.

Parameters

window : nsIDOMWindow

uri : string,
nsIURI}

type : string
The type of the sheet. It accepts the following values: "agent", "user" and "author". If not provided, the default value is "author".

isTypeValid(type)

Verifies that the type given is a valid stylesheet's type. The values considered valid are: "agent", "user" and "author".

Parameters

type : string
The type of the sheet.

Returns

boolean : true if the type given is valid, otherwise false.

Document Tags and Contributors

 Contributors to this page: wbamberg
 Last updated by: wbamberg,