messageDisplayScripts

This message display scripts API first appeared in Thunderbird 82 and was backported to Thunderbird 78.4. Functionally it is the same as the content scripts API except that it works on the document of email messages being displayed. See the MDN documentation for a more in-depth explanation and Changes in Thunderbird 78.4.0 for examples.

See also executeScript, insertCSS, removeCSS, and composeScripts.

Note

Registering a message display script through manifest.json is not possible at this point.

Permissions

messagesModify
Read and modify your email messages as they are displayed to you

Note

The permission messagesModify is required to use messageDisplayScripts.

Functions

register(messageDisplayScriptOptions)

Register a message display script programmatically

Parameters
messageDisplayScriptOptions
Required permissions
  • messagesModify

Types

RegisteredMessageDisplayScript

An object that represents a message display script registered programmatically

object
  • unregister() Unregister a message display script registered programmatically

RegisteredMessageDisplayScriptOptions

Details of a message display script registered programmatically

object
[css]
The list of CSS files to inject
[js]
The list of JavaScript files to inject

External Types

The following types are not defined by this API, but by the underlying Mozilla WebExtension code base. They are included here, because there is no other public documentation available.

ExtensionFileOrCode

Specify code, either by pointing to a file or by providing the code directly. Only one of the two is allowed.

object
code
(string)
Some JavaScript code to register.
file
(string)
A URL starting at the extension’s manifest.json and pointing to a JavaScript file to register.