The
readAsDataURL() method of the FileReaderSync interface allows to read File or Blob objects in a synchronous way into an DOMString representing a data URL. This interface is only available in workers as it enables synchronous I/O that could potentially block.Syntax
readAsDataURL(File); readAsDataURL(Blob);
Parameters
Return value
An DOMString representing the input data as a data URL.
Exceptions
The following exceptions can be raised by this method:
NotFoundError- is raised when the resource represented by the DOM
FileorBlobcannot 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 'readAsDataURL' 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 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
readAsDataURL | 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