Blob.slice()

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

Syntax

var newBlob = blob.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

Browser compatibility

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See also

• Blob
• Using files from web applications