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.

var newBlob = blob.slice(start, end, contentType);

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.

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.

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

• Blob
• Using files from web applications