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 Blob
s and File
s.
See Using files from web applications for more information and examples.
Blob File
File.prototype.lastModified
Read only
Returns the last modified time of the file, in millisecond since the UNIX epoch (January 1st, 1970 at Midnight).
File.prototype.lastModifiedDate
Deprecated Read only Non-standard
Returns the last modified Date
of the file referenced by the File
object.
File.prototype.name
Read only
Returns the name of the file referenced by the File
object.
File.prototype.webkitRelativePath
Read only
Returns the path the URL of the File
is relative to.
File
implements Blob
, so it also has the following properties available to it:
Blob.size
Read only
Returns the size of the file in bytes.
File.prototype.type
Read only
Returns the MIME type of the file.
The File
interface doesn't define any methods, but inherits methods from the Blob
interface:
Blob.prototype.slice([start[, end[, contentType]]])
Returns a new Blob
object containing the data in the specified range of bytes of the source Blob
.
Blob.prototype.stream()
Transforms the File
into a ReadableStream
that can be used to read the File
contents.
Blob.prototype.text()
Transforms the File
into a stream and reads it to completion. It returns a promise that resolves with a string (text).
Blob.prototype.arrayBuffer()
Transforms the File
into a stream and reads it to completion. It returns a promise that resolves with an ArrayBuffer
.