1. Web
  2. Web APIs
  3. FileReaderSync

FileReaderSync

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 only available in Web Workers, except for Service Workers.

The FileReaderSync interface allows to read File or Blob objects synchronously. This interface is only available in workers as it enables synchronous I/O that could potentially block.

Constructor

FileReaderSync()

Returns a new FileReaderSync object.

Instance properties

This interface does not have any properties.

Instance methods

FileReaderSync.readAsArrayBuffer()

This method converts a specified Blob or a File into an ArrayBuffer representing the input data as a binary string.

FileReaderSync.readAsBinaryString()

This method converts a specified Blob or a File into a string representing the input data as a binary string. This method is deprecated, consider using readAsArrayBuffer() instead.

FileReaderSync.readAsText()

This method converts a specified Blob or a File into a string representing the input data as a text string. The optional encoding parameter indicates the encoding to be used (e.g., iso-8859-1 or UTF-8). If not present, the method will apply a detection algorithm for it.

FileReaderSync.readAsDataURL()

This method converts a specified Blob or a File into a string representing the input data as a data URL.

Specifications

Specification
File API
# FileReaderSync

Browser compatibility

Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
FileReaderSync
Chrome – Full support
Chrome 7 (Release date: 2010-10-19)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 8 (Release date: 2011-11-08)
footnote Full support
Opera – Full support
Opera 12.1 (Release date: 2012-11-20)
footnote Full support
Safari – Full support
Safari 6 (Release date: 2012-07-25)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 8 (Release date: 2011-11-08)
footnote Full support
Opera Android – Full support
Opera Android 12.1 (Release date: 2012-10-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 6 (Release date: 2012-09-10)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – No support
Deno
footnote No support
FileReaderSync() constructor
Chrome – Full support
Chrome 7 (Release date: 2010-10-19)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 8 (Release date: 2011-11-08)
footnote Full support
Opera – Full support
Opera 12.1 (Release date: 2012-11-20)
footnote Full support
Safari – Full support
Safari 6 (Release date: 2012-07-25)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 8 (Release date: 2011-11-08)
footnote Full support
Opera Android – Full support
Opera Android 12.1 (Release date: 2012-10-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 6 (Release date: 2012-09-10)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – No support
Deno
footnote No support
readAsArrayBuffer
Chrome – Full support
Chrome 9 (Release date: 2011-02-03)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 8 (Release date: 2011-11-08)
footnote Full support
Opera – Full support
Opera 12.1 (Release date: 2012-11-20)
footnote Full support
Safari – Full support
Safari 6 (Release date: 2012-07-25)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 8 (Release date: 2011-11-08)
footnote Full support
Opera Android – Full support
Opera Android 12.1 (Release date: 2012-10-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 6 (Release date: 2012-09-10)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – No support
Deno
footnote No support
readAsBinaryString
Deprecated
Chrome – Full support
Chrome 7 (Release date: 2010-10-19)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 8 (Release date: 2011-11-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 6 (Release date: 2012-07-25)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 8 (Release date: 2011-11-08)
footnote Full support
Opera Android – Full support
Opera Android 14 (Release date: 2013-05-21)
footnote Full support
Safari on iOS – Full support
Safari on iOS 6 (Release date: 2012-09-10)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – No support
Deno
footnote No support
readAsDataURL
Chrome – Full support
Chrome 7 (Release date: 2010-10-19)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 8 (Release date: 2011-11-08)
footnote Full support
Opera – Full support
Opera 12.1 (Release date: 2012-11-20)
footnote Full support
Safari – Full support
Safari 6 (Release date: 2012-07-25)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 8 (Release date: 2011-11-08)
footnote Full support
Opera Android – Full support
Opera Android 12.1 (Release date: 2012-10-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 6 (Release date: 2012-09-10)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – No support
Deno
footnote No support
readAsText
Chrome – Full support
Chrome 7 (Release date: 2010-10-19)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 8 (Release date: 2011-11-08)
footnote Full support
Opera – Full support
Opera 12.1 (Release date: 2012-11-20)
footnote Full support
Safari – Full support
Safari 6 (Release date: 2012-07-25)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 8 (Release date: 2011-11-08)
footnote Full support
Opera Android – Full support
Opera Android 12.1 (Release date: 2012-10-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 6 (Release date: 2012-09-10)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – No support
Deno
footnote No support
Available in workers
Chrome – Full support
Chrome 7 (Release date: 2010-10-19)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 8 (Release date: 2011-11-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 6 (Release date: 2012-07-25)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 8 (Release date: 2011-11-08)
footnote Full support
Opera Android – Full support
Opera Android 14 (Release date: 2013-05-21)
footnote Full support
Safari on iOS – Full support
Safari on iOS 6 (Release date: 2012-09-10)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – No support
Deno
footnote No support

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Full support
No support
Deprecated. Not for use in new websites.

See also

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