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.
open method returns a
LockedFile object that allows to
safely write in the file.
var myFile = instanceOfFileHandle.open(mode);
A string that specifies the writing mode for the file. It can be
This feature is not part of any current specification. It is no longer on track to become a standard.