File
The File interface provides information about files and allows JavaScript in a web page to access their content.
File objects are generally retrieved from a FileList object returned as a result of a user selecting files using the <input> element, or from a drag and drop operation's DataTransfer object.
A File object is a specific kind of Blob, and can be used in any context that a Blob can. In particular, FileReader, URL.createObjectURL(), createImageBitmap(), and XMLHttpRequest.send() accept both Blobs and Files.
See Using files from web applications for more information and examples.
Constructor
File()-
Returns a newly constructed
File.
Instance properties
File.prototype.lastModifiedRead only-
Returns the last modified time of the file, in millisecond since the UNIX epoch (January 1st, 1970 at Midnight).
File.prototype.lastModifiedDateDeprecated Read only Non-standard-
Returns the last modified
Dateof the file referenced by theFileobject. File.prototype.nameRead only-
Returns the name of the file referenced by the
Fileobject. File.prototype.webkitRelativePathRead only-
Returns the path the URL of the
Fileis relative to.
File implements Blob, so it also has the following properties available to it:
File.prototype.sizeRead only-
Returns the size of the file in bytes.
File.prototype.typeRead only-
Returns the MIME type of the file.
Instance methods
The File interface doesn't define any methods, but inherits methods from the Blob interface:
Blob.prototype.slice([start[, end[, contentType]]])-
Returns a new
Blobobject containing the data in the specified range of bytes of the sourceBlob. Blob.prototype.stream()-
Transforms the
Fileinto aReadableStreamthat can be used to read theFilecontents. Blob.prototype.text()-
Transforms the
Fileinto a stream and reads it to completion. It returns a promise that resolves with a string (text). Blob.prototype.arrayBuffer()-
Transforms the
Fileinto a stream and reads it to completion. It returns a promise that resolves with anArrayBuffer.
Specifications
| Specification |
|---|
| File API # file-section |
Browser compatibility
BCD tables only load in the browser