The soonest that the JavaScript or CSS will be injected into the tab.


Values of this type are strings. Possible values are: "document_start", "document_end", "document_idle".

Browser compatibility

Chrome Edge Firefox Firefox for Android Opera
Basic Support Yes Yes 45.0 48.0 33


This API is based on Chromium's chrome.extensionTypes API. This documentation is derived from extension_types.json in the Chromium code.

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.

Document Tags and Contributors

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