The readAsBinaryString
method is used to start reading the contents of the specified Blob
or File
. When the read operation is finished, the readyState
becomes DONE
, and the loadend
is triggered. At that time, the result
attribute contains the raw binary data from the file.
Note that this method was once removed from the File API specification, but re-introduced for backward compatibility.
Using FileReader.readAsArrayBuffer()
is recommended.
Syntax
instanceOfFileReader.readAsBinaryString(blob);
Parameters
Example
var canvas = document.createElement('canvas'); var height = 200; var width = 200; canvas.width = width; canvas.height = height; var ctx = canvas.getContext('2d'); ctx.strokeStyle = '#090'; ctx.beginPath(); ctx.arc(width/2, height/2, width/2 - width/10, 0, Math.PI*2); ctx.stroke(); canvas.toBlob(function (blob) { var reader = new FileReader(); reader.onload = function () { console.log(reader.result); } reader.readAsBinaryString(blob); });
Specifications
Specification | Status | Comment |
---|---|---|
File API The definition of 'readAsBinaryString' in that specification. |
Working Draft |
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.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
readAsBinaryString | Chrome Full support 7 | Edge Full support 12 | Firefox Full support 3.6 | IE No support No | Opera Full support 11 | Safari Full support 6 | WebView Android Full support ≤37 | Chrome Android Full support 18 | Firefox Android Full support 32 | Opera Android Full support 11 | Safari iOS Full support 6.1 | Samsung Internet Android Full support 1.0 |
Legend
- Full support
- Full support
- No support
- No support