Web/API/File and Directory Entries API

Non-standard This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The File and Directory Entries API simulates a local file system that web apps can navigate within and access files in. You can develop apps which read, write, and create files and/or directories in a virtual, sandboxed file system.

Because this is a non-standard API, whose specification is not currently on a standards track, it's important to keep in mind that not all browsers implement it, and those that do may implement only small portions of it. Check the Browser compatibility section for details.

Two very similar APIs exist depending on whether you desire asynchronous or synchronous behavior. The synchronous API is intended to be used inside a Worker and will return the values you desire. The asynchronous API will not block and functions and the API will not return values; instead, you will need to supply a callback function to handle the response whenever it arrives.

The Firefox implementation of the File and Directory Entries API is very limited; there is no support for creating files. Only for accessing files which are selected by the user in a file <input> element (see HTMLInputElement as well) or when a file or directory is provided to the Web site or app using drag and drop. Firefox also does not implement the synchronous API. Check the browser compatibility for any part of the API you use carefully, and see File and Directory Entries API support in Firefox for more details.

Getting access to a file system

There are two ways to get access to file systems defined in the current specification draft:

• When handling a drop event for drag and drop, you can call DataTransferItem.webkitGetAsEntry() to get the FileSystemEntry for a dropped item. If the result isn't null, then it's a dropped file or directory, and you can use file system calls to work with it.
• The HTMLInputElement.webkitEntries property lets you access the FileSystemFileEntry objects for the currently selected files, but only if they are dragged-and-dropped onto the file chooser (bug 1326031). If HTMLInputElement.webkitdirectory is true, the <input> element is instead a directory picker, and you get FileSystemDirectoryEntry objects for each selected directory.

Asynchronous API

The asynchronous API should be used for most operations, to prevent file system accesses from blocking the entire browser if used on the main thread. It includes the following interfaces:

FileSystem

Represents a file system.

FileSystemEntry

The basic interface representing a single entry in a file system. This is implemented by other interfaces which represent files or directories.

FileSystemFileEntry

Represents a single file in a file system.

FileSystemDirectoryEntry

Represents a single directory in a file system.

FileSystemDirectoryReader

Created by calling FileSystemDirectoryEntry.createReader(), this interface provides the functionality which lets you read the contents of a directory.

FileSystemFlags

Defines a set of values which are used when specifying option flags when calling certain methods in the File and Directory Entries API.

FileError  '

Represents an error which is generated by asynchronous file system calls.

There are also two global functions (which are not part of the specification at this time and are implemented only by Google Chrome). They're available on the Window object and implemented in LocalFileSystem: requestFileSystem() and resolveLocalFileSystemURL().

Synchronous API

The synchronous API is should only be used in Workers; these calls block until they're finished executing, and simply return the results instead of using callbacks. Using them on the main thread will block the browser, which is naughty. The interfaces below otherwise mirror the ones from the asynchronous API.

FileSystemSync

Represents a file system.

FileSystemEntrySync

The basic interface representing a single entry in a file system. This is implemented by other interfaces which represent files or directories.

FileSystemFileEntrySync

Represents a single file in a file system.

FileSystemDirectoryEntrySync

Represents a single directory in a file system.

FileSystemDirectoryReaderSync

Created by calling FileSystemDirectoryEntrySync.createReader(), this interface provides the functionality which lets you read the contents of a directory.

FileException  '

Represents an error which is generated by synchronous file system calls.

There are also two global functions (which are not part of the specification at this time and are implemented only by Google Chrome). They're available on the Worker object and implemented in LocalFileSystemSync: requestFileSystemSync() and resolveLocalFileSystemSyncURL().

Other Interfaces

LocalFileSystem

Gives you access to a sandboxed file system.

LocalFileSystemSync

LockedFile

Provides tools to deal with a given file with all the necessary locks.

Metadata '

Specifications

Specification	Status	Comment
File and Directory Entries API	Draft	Draft of proposed API

This API has no official W3C or WHATWG specification.

Browser compatibility

FileSystem

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
FileSystem	Chrome Full support 7 Alternate Name' Full support 7 Alternate Name' Alternate Name' Uses the non-standard name: DOMFileSystem	Edge Full support ≤18 Prefixed' Notes' Full support ≤18 Prefixed' Notes' Prefixed' Implemented with the vendor prefix: WebKit Notes' Edge only supports this API in drag-and-drop scenarios using the the DataTransferItem.webkitGetAsEntry() method. It's not available for use in file or folder picker panels (such as when you use an <input> element with the HTMLInputElement.webkitdirectory attribute.	Firefox Full support 50	IE No support No	Opera Full support 15 Prefixed' Full support 15 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari Full support 11.1	WebView Android Full support ≤37 Alternate Name' Full support ≤37 Alternate Name' Alternate Name' Uses the non-standard name: DOMFileSystem	Chrome Android Full support 18 Alternate Name' Full support 18 Alternate Name' Alternate Name' Uses the non-standard name: DOMFileSystem	Firefox Android Full support 50	Opera Android Full support 14 Prefixed' Full support 14 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari iOS Full support 11.3	Samsung Internet Android Full support 1.0 Prefixed' Full support 1.0 Prefixed' Prefixed' Implemented with the vendor prefix: webkit

Legend

Full support  

Full support

No support  

No support

See implementation notes.'

See implementation notes.

Uses a non-standard name.'

Uses a non-standard name.

Requires a vendor prefix or different name for use.'

Requires a vendor prefix or different name for use.

FileSystemSync property

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
FileSystemSync Non-standard'	Chrome Full support 13 Prefixed' Full support 13 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support ≤79 Prefixed' Full support ≤79 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Firefox No support No	IE No support No	Opera Full support 15 Prefixed' Full support 15 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari Full support 6 Prefixed' Full support 6 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	WebView Android Full support ≤37 Prefixed' Full support ≤37 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 18 Prefixed' Full support 18 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Firefox Android No support No	Opera Android Full support 14 Prefixed' Full support 14 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari iOS Full support 6 Prefixed' Full support 6 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Samsung Internet Android Full support 1.0 Prefixed' Full support 1.0 Prefixed' Prefixed' Implemented with the vendor prefix: webkit

Legend

Full support  

Full support

No support  

No support

Non-standard. Expect poor cross-browser support.'

Non-standard. Expect poor cross-browser support.

Requires a vendor prefix or different name for use.'

Requires a vendor prefix or different name for use.

See also

• Introduction to the File and Directory Entries API
• File and Directory Entries API support in Firefox

File and Directory Entries API by Mozilla Contributors is licensed under CC-BY-SA 2.5.