Blob: slice() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

See full compatibility

Note: This feature is available in Web Workers.

The slice() method of the Blob interface creates and returns a new Blob object which contains data from a subset of the blob on which it's called.

Syntax

slice()
slice(start)
slice(start, end)
slice(start, end, contentType)

Parameters

start Optional: An index into the Blob indicating the first byte to include in the new Blob. If you specify a negative value, it's treated as an offset from the end of the Blob toward the beginning. For example, -10 would be the 10th from last byte in the Blob. The default value is 0. If you specify a value for start that is larger than the size of the source Blob, the returned Blob has size 0 and contains no data.
end Optional: An index into the Blob indicating the first byte that will not be included in the new Blob (i.e., the byte exactly at this index is not included). If you specify a negative value, it's treated as an offset from the end of the Blob toward the beginning. For example, -10 would be the 10th from last byte in the Blob. The default value is size.
contentType Optional: The content type to assign to the new Blob; this will be the value of its type property. The default value is an empty string.

Return value

A new Blob object containing the specified subset of the data contained within the blob on which this method was called. The original blob is not altered.

Specifications

Specification
File API # dfn-slice

Browser compatibility

	desktop					mobile							server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS	Bun	Deno	Node.js
`slice()`	Chrome – No support Chrome 5 – 24 (Release date: 2010-05-25) prefix footnote Removed in 25 and later prefix Implemented with the vendor prefix: webkit Chrome – Full support Chrome 21 (Release date: 2012-07-31) footnote Full support	Edge – Full support Edge 12 (Release date: 2015-07-29) footnote Full support	Firefox – No support Firefox 5 – 12 (Release date: 2011-06-21) prefix prefix Implemented with the vendor prefix: moz Firefox – Full support Firefox 13 (Release date: 2012-06-05) footnote footnote Before Firefox 12, there was a bug that affected the behavior of `Blob.slice()`; it did not work for `start` and `end` positions outside the range of signed 64-bit values; it has now been fixed to support unsigned 64-bit values.	Opera – Full support Opera 12 (Release date: 2012-06-14) footnote Full support	Safari – No support Safari 6 – 6 (Release date: 2012-07-25) prefix prefix Implemented with the vendor prefix: webkit Safari – Full support Safari 7 (Release date: 2013-10-22) footnote Full support	Chrome Android – No support Chrome Android 18 – 18 (Release date: 2012-06-27) prefix prefix Implemented with the vendor prefix: webkit Chrome Android – Full support Chrome Android 25 (Release date: 2013-02-27) footnote Full support	Firefox for Android – No support Firefox for Android 5 – 10 (Release date: 2011-06-21) prefix prefix Implemented with the vendor prefix: moz Firefox for Android – Full support Firefox for Android 14 (Release date: 2012-06-26) footnote footnote Before Firefox for Android 14, there was a bug that affected the behavior of `Blob.slice()`; it did not work for `start` and `end` positions outside the range of signed 64-bit values; it has now been fixed to support unsigned 64-bit values.	Opera Android – Full support Opera Android 12 (Release date: 2012-02-25) footnote Full support	Safari on iOS – No support Safari on iOS 6 – 6 (Release date: 2012-09-10) prefix prefix Implemented with the vendor prefix: webkit Safari on iOS – Full support Safari on iOS 7 (Release date: 2013-09-18) footnote Full support	Samsung Internet – No support Samsung Internet 1 – 1 (Release date: 2013-04-27) prefix prefix Implemented with the vendor prefix: webkit Samsung Internet – Full support Samsung Internet 1.5 (Release date: 2013-09-25) footnote Full support	WebView Android – Full support WebView Android 4.4 (Release date: 2013-12-09) footnote Full support	WebView on iOS – No support WebView on iOS 6 – 6 (Release date: 2012-09-10) prefix prefix Implemented with the vendor prefix: webkit WebView on iOS – Full support WebView on iOS 7 (Release date: 2013-09-18) footnote Full support	Bun – Full support Bun 1 (Release date: 2023-09-08) footnote Full support	Deno – Full support Deno 1 (Release date: 2020-05-13) footnote Full support	Node.js – No support Node.js 14.18 – 14.18 (Release date: 2021-09-28) footnote Removed in 15 and later Node.js – Full support Node.js 15.7 (Release date: 2021-01-26) footnote Full support

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Full support: Full support
: See implementation notes.
: Requires a vendor prefix or different name for use.
: Has more compatibility info.