FileSystemFileEntry: createWriter() method

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.

Non-standard: This feature is not standardized. We do not recommend using non-standard features in production, as they have limited browser support, and may change or be removed. However, they can be a suitable alternative in specific cases where no standard option exists.

The FileSystemFileEntry interface's method createWriter() returns a FileWriter object which can be used to write data into the file represented by the directory entry.

Syntax

createWriter(successCallback)
createWriter(successCallback, errorCallback)

Parameters

successCallback: A callback function which is called when the FileWriter has been created successfully; the FileWriter is passed into the callback as the only parameter.
errorCallback Optional: If provided, this must be a method which is called when an error occurs while trying to create the FileWriter. This callback receives as input a DOMException object describing the error.

Return value

None (undefined).

Examples

This example establishes a method, writeToFileEntry(), which outputs a text string to the file corresponding to the passed-in directory entry.

function writeToFileEntry(entry, text) {
  entry.createWriter(
    (fileWriter) => {
      let data = Blob([text], { type: "text/plain" });

      fileWriter.write(data);
    },
    (error) => {
      /* do whatever to handle the error */
    },
  );
}

The success callback for the createWriter() call takes the text which was passed in and creates a new Blob object of type text/plain that contains the passed text. This blob is then output to the FileWriter object to be written to the file.

Specifications

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

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`createWriter` Deprecated Non-standard	Chrome – Full support Chrome 8 (Release date: 2010-12-02) footnote Full support	Edge – Full support Edge 79 (Release date: 2020-01-15) footnote Full support	Firefox – No support Firefox 50 – 51 (Release date: 2016-11-15) footnote Removed in 52 and later footnote While the `createWriter()` method existed, it immediately called `errorCallback` with the `NS_ERROR_DOM_SECURITY_ERR` error.	Opera – Full support Opera 15 (Release date: 2013-07-02) footnote Full support	Safari – No support Safari footnote No support	Chrome Android – Full support Chrome Android 18 (Release date: 2012-06-27) footnote Full support	Firefox for Android – No support Firefox for Android 50 – 51 (Release date: 2016-11-15) footnote Removed in 52 and later footnote While the `createWriter()` method existed, it immediately called `errorCallback` with the `NS_ERROR_DOM_SECURITY_ERR` error.	Opera Android – Full support Opera Android 14 (Release date: 2013-05-21) footnote Full support	Safari on iOS – No support Safari on iOS footnote No support	Samsung Internet – Full support Samsung Internet 1 (Release date: 2013-04-27) footnote Full support	WebView Android – Full support WebView Android 4.4 (Release date: 2013-12-09) footnote Full support	WebView on iOS – No support WebView on iOS footnote No support

Tip: you can click/tap on a cell for more information.

Full support: Full support
No support: No support
: Non-standard. Check cross-browser support before using.
: Deprecated. Not for use in new websites.