The File object provides information about -- and access to the contents of -- files. These 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.
Starting in Gecko 2.0 (Firefox 4 / Thunderbird 3.3 / SeaMonkey 2.1) , the File object inherits from the Blob interface, which provides methods and properties providing further information about the file.
The file reference can be saved when the form is submitted while the user is offline, so that the data can be retrieved and uploaded when the Internet connection is restored.
Documentation for this class was provided by MDN. var lastModifiedDate(default,null) : Date var name(default,null) : StringThe name of the file referenced by the File object. Read only. Requires Gecko 1.9.2 var relativePath(default,null) : String