The FilenameConflictAction type of the downloads API specifies what to do if the name of a downloaded file conflicts with an existing file.

This type defines the values that can be used for the conflictAction property of the function's options parameter.


Values of this type are strings. Possible values are:

The browser will modify the filename to make it unique.
The browser will overwrite the old file with the newly-downloaded file.
The browser will prompt the user, asking them to choose whether to uniquify or overwrite.

Browser compatibility

Chrome Edge Firefox Firefox for Android Opera
Basic Support Yes No 47.0 48.0 33

Compatibility notes


  • 'prompt' is not supported.

Firefox for Android

  • 'prompt' is not supported.


This API is based on Chromium's chrome.downloads API.

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, chrisdavidmills
 Last updated by: wbamberg,