Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Note: The three non-standard interfaces IDBMutableFile, IDBFileHandle, and IDBFileRequest are disabled by default. Consider using the File and Directory Entries API instead.

The truncate method of the IDBFileHandle interface removes some data within the file.

If the method is called with no argument, the operation removes all the bytes starting at the index set in location.

If the method is called with an argument, the operation removes all the bytes starting at the index corresponding to the parameter and regardless of the value of location.




start Optional

A number representing the index where to start the operation.

Return value

An IDBFileRequest` object to handle the success or failure of the operation.


This feature is not part of any current specification. It is no longer on track to become a standard.

Browser compatibility

This method is not supported by any current browser. From Firefox 102 it is behind the preference dom.fileHandle.enabled.

See also