FileReader.readyState - Web APIs 编辑

The FileReader readyState property provides the current state of the reading operation a FileReader is in. A FileReader exists in one of the following states:

EMPTY

The FileReader has been created, but no readAs method was called yet.

LOADING

A readAs method was invoked. A File or Blob is being read, and no error has occurred yet.

DONE

The read operation is complete. This could mean that: the entire File or Blob has been read into memory, a file read error occurred, or abort() was called and the read was cancelled.

Example

var reader = new FileReader();
console.log('EMPTY', reader.readyState); // readyState will be 0

reader.readAsText(blob);
console.log('LOADING', reader.readyState); // readyState will be 1

reader.onloadend = function () {
  console.log('DONE', reader.readyState); // readyState will be 2
};

Value

A number which is one of the three possible state constants define for the FileReader API.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Blob