The Blob.slice() method is used to create a new Blob object containing the data in the specified range of bytes of the source Blob.
Note: Be aware that the
slice() method has vendor prefixes on some browsers and versions: blob.mozSlice() for Firefox 12 and earlier and blob.webkitSlice() in Safari. An old version of the slice() method, without vendor prefixes, had different semantics, and is obsolete.Syntax
var blob = instanceOfBlob.slice([start [, end [, contentType]]]);
Parameters
startOptional- An index into the
Blobindicating the first byte to include in the newBlob. If you specify a negative value, it's treated as an offset from the end of the string toward the beginning. For example, -10 would be the 10th from last byte in theBlob. The default value is 0. If you specify a value forstartthat is larger than the size of the sourceBlob, the returnedBlobhas size 0 and contains no data. endOptional- An index into the
Blobindicating the first byte that will *not* be included in the newBlob(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 string toward the beginning. For example, -10 would be the 10th from last byte in theBlob. The default value issize. contentTypeOptional- The content type to assign to the new
Blob; this will be the value of itstypeproperty. The default value is an empty string.
Return value
A new Blob object containing the specified data from the source Blob.
Specifications
| Specification | Status | Comment |
|---|---|---|
| File API The definition of 'Blob.slice()' in that specification. |
Working Draft | Initial definition |
Browser compatibility
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.
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 21 5 — 21 webkit | 12 | 131 5 — 13 moz | 10 | 12 | 5.1 webkit |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
|---|---|---|---|---|---|---|---|
| Basic support | ? | ? | Yes | 14 | ? | ? | ? |
1. Prior to Gecko 12.0 (Firefox 12.0 / Thunderbird 12.0 / SeaMonkey 2.9), 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.