Chrome extension: message from background.js to content.js

Question

I am trying to send a message from background.js to content.js using the following code:

Background

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Answer 1

There are 2 sendMessage functions in Chrome API.

• chrome.runtime.sendMessage sends a message to all open extension pages (i.e. background, popup, etc.)
• chrome.tabs.sendMessage sends a message to all content scripts from the extension in a given tab (possibly filtered by frame ID)

So, to send a message TO a content script, you need to use chrome.tabs. To send a message FROM a content script (or within the extension pages), you need to use chrome.runtime.

The event is chrome.runtime.onMessage in both cases.

See Messaging docs for more details.