var state = instanceOfFileReader.readyState


數字代表 FileReader API 三個可能的狀態:

{{page("/en-US/docs/Web/API/FileReader","State constants")}}


規格 狀態 說明
File API
The definition of 'FileReader' in that specification.
Working Draft 初始化定義


We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help! (en-US)

功能 Firefox (Gecko) Chrome Internet Explorer Opera Safari
基本支援 3.6 (1.9.2)[1] 7 10[2] 12.02[3] 6.0.2
功能 Firefox 手機版 (Gecko) Android IE 手機版 Opera 手機版 Safari 手機版
基本支援 32 3 10 11.5 6.1

[1] Prior to Gecko 2.0 beta 7 (Firefox 4.0 beta 7), all Blob parameters below were File parameters; this has since been updated to match the specification correctly. Prior to Gecko 13.0 (Firefox 13.0 / Thunderbird 13.0 / SeaMonkey 2.10) the FileReader.error property returned a FileError (en-US) object. This interface has been removed and FileReader.error is now returning the DOMError (en-US) object as defined in the latest FileAPI draft.

[2] IE9 has a File API Lab.

[3] Opera has partial support in 11.1.