The readAsDataURL()
method of the FileReaderSync
interface allows to read File
or Blob
objects in a synchronous way into a string representing a data URL. This interface is only available in workers as it enables synchronous I/O that could potentially block.
readAsDataURL(File)
readAsDataURL(Blob)
A string representing the input data as a data URL.
The following exceptions can be raised by this method:
-
NotFoundError
DOMException
-
Thrown if the resource represented by the DOM File
or Blob
cannot be found, e.g. because it has been erased.
-
SecurityError
DOMException
-
Thrown if 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
DOMException
-
Thrown if the resource cannot be read due to a permission problem, like a concurrent lock.
-
EncodingError
DOMException
-
Thrown if the resource is a data URL and exceed the limit length defined by each browser.