This is an experimental feature
Because this feature is still in development in some browsers, check the compatibility table for the proper prefixes to use in various browsers.
A Blob
object represents a file-like object of immutable, raw data. Blobs represent data that isn't necessarily in a JavaScript-native format. The File
interface is based on Blob
, inheriting blob functionality and expanding it to support files on the user's system.
An easy way to construct a Blob
is by using the BlobBuilder
interface, which lets you iteratively append data to a blob, then retrieve the completed blob when you're ready to use it for something. Another way is to use the slice()
method to create a blob that contains a subset of another blob's data.
slice()
method has vendor prefixes: blob.mozSlice()
for Firefox and blob.webkitSlice()
for Chrome. An old version of the slice()
method, without vendor prefixes, had different semantics, as described below.Blob
object. Read only.Blob
. If the type is unknown, this string is empty. Read only.