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 FileReaderSync
interface allows to read File
or Blob
objects in a synchronous way into an DOMString
. This interface is only available in workers as it enables synchronous I/O that could potentially block.Syntax
readAsBinaryString(File); readAsBinaryString(Blob);
Parameters
Return value
An DOMString
representing the input data.
Exceptions
The following exceptions can be raised by this method:
NotFoundError
- is raised when the resource represented by the DOM
File
orBlob
cannot be found, e.g. because it has been erased. SecurityError
- is raised when one of the following problematic situation is detected:
- the resource has been modified by a third party;
- too many read are performed simultaneously;
- the file pointed by the resource is unsafe for a use from the Web (like it is a system file).
NotReadableError
- is raised when the resource cannot be read due to a permission problem, like a concurrent lock.
EncodingError
- is raised when the resource is a data URL and exceed the limit length defined by each browser.
Specifications
Specification | Status | Comment |
---|---|---|
File API The definition of 'readAsBinaryStringSync' 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.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
readAsBinaryString | Chrome Full support Yes | Edge Full support 12 | Firefox Full support 8 | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 8 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support