FileReader
result
property returns the file's contents. This property is only valid after the read operation is complete, and the format of the data depends on which of the methods was used to initiate the read operation.
var file = instanceOfFileReader.result
An appropiate string or
ArrayBuffer
based on which of the reading methods was used to initiate the read operation. The value is
null
if the reading is not yet complete or was unsuccessful.
The result types are described below.
| 方法 | 描述 |
|---|---|
readAsArrayBuffer()
|
result
is a JavaScript
ArrayBuffer
containing binary data.
|
readAsBinaryString()
|
result
contains the raw binary data from the file in a string.
|
readAsDataURL()
|
result
is a string with a
data:
URL representing the file's data.
|
readAsText()
|
result
is text in a string.
|
This example presents a function,
read()
, which reads a file from a
file input
. It works by creating a
FileReader
object and creating a listener for
load
events such that when then file is read, the
result
is obtained and passed to the callback function provided to
read()
.
The content is handled as raw text data.
var fileInput = document.querySelector('input[type="file"]');
function read(callback) {
var file = fileInput.files.item(0);
var reader = new FileReader();
reader.onload = function() {
callback(reader.result);
}
reader.readAsText(file);
}
| 规范 | 状态 | 注释 |
|---|---|---|
|
文件 API
The definition of 'result' in that specification. |
工作草案 | 初始定义 |
| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
result
|
Chrome 7 | Edge 12 | Firefox 3.6 | IE 10 | Opera 11 | Safari 6 | WebView Android Yes | Chrome Android Yes | Firefox Android 32 | Opera Android 11 | Safari iOS 6.1 | Samsung Internet Android Yes |
完整支持
FileReader
error
onabort
onload
readyState
result