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.
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The read-only size
property of the Metadata
interface specifies the size, in bytes, of the referenced file or other file system object on disk.