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提供 FileReader 读取操作时的当前状态。


var state = instanceOfFileReader.readyState

一个数字,用来表示 FileReader API 的三种可能状态。


Specification Status Comment
File API
Working Draft Initial definition


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!

Feature Firefox (Gecko) Chrome Internet Explorer Opera Safari
Basic support 3.6 (1.9.2)[1] 7 10[2] 12.02[3] 6.0.2
Feature Firefox Mobile (Gecko) Android IE Mobile Opera Mobile Safari Mobile
Basic support 32 3 10 11.5 6.1

[1] 在Gecko 2.0 beta 7 (Firefox 4.0 beta 7)之前,上述方法中所有的 Blob 参数都只能是一个 File 对象。根据最新的 FileAPI 草案,现在的所有的 Blob 参数既可以是 Blob 对象也可以是一个 File 对象。在Gecko 13.0 (Firefox 13.0 / Thunderbird 13.0 / SeaMonkey 2.10) 之前,FileReader.error 属性会返回一个 FileError 对象。根据最新的FileAPI草案,现在的  FileReader.error会返回一个 DOMError 对象。

[2] IE9有一个 File API Lab.

[3] Opera从11.10开始 部分支持 .



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