FileReader: readAsBinaryString() method
Note: This feature is available in Web Workers.
Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.
Note:
This method is deprecated in favor of readAsArrayBuffer().
The readAsBinaryString() method of the FileReader interface is used to start reading the contents of the
specified Blob or File. When the read operation is
finished, the readyState property becomes
DONE, and the loadend event is triggered. At that time, the
result property 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
readAsBinaryString(blob)
Parameters
Return value
None (undefined).
Examples
const canvas = document.createElement("canvas");
const height = 200;
const width = 200;
canvas.width = width;
canvas.height = height;
const ctx = canvas.getContext("2d");
ctx.strokeStyle = "#009900";
ctx.beginPath();
ctx.arc(width / 2, height / 2, width / 2 - width / 10, 0, Math.PI * 2);
ctx.stroke();
canvas.toBlob((blob) => {
const reader = new FileReader();
reader.onload = () => {
console.log(reader.result);
};
reader.readAsBinaryString(blob);
});
Specifications
| Specification |
|---|
| File API # readAsBinaryString |
Browser compatibility
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readAsBinaryString
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
- Deprecated. Not for use in new websites.