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.

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

js
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

See also