BlobBuilder

The BlobBuilder interface provides an easy way to construct Blob objects. Just create a BlobBuilder and append chunks of data to it by calling the append() method. When you're done building your blob, call getBlob() to retrieve a Blob containing the data you sent into the blob builder.

方法概述

方法

append()

Appends the contents of the specified JavaScript object to the Blob being built. If the value you specify isn't a Blob, ArrayBuffer, or String, the value is coerced to a string before being appended to the blob.

void append(
  in ArrayBuffer data
);
void append(
  in Blob data
);
void append(
  in String data,
  [optional] in String endings
);

参数

data

The data to append to the Blob being constructed.

endings

Specifies how strings containing \n are to be written out. This can be "transparent" (endings unchanged) or "native" (endings changed to match host OS filesystem convention). The default value is "transparent".

getBlob()

Returns the Blob object that has been constructed using the data passed through calls to append().

Blob getBlob(
  in DOMString contentType 可选
);

参数

contentType 可选

The MIME type of the data to be returned in the Blob. This will be the value of the Blob object's type property.

返回值

A Blob object containing all of the data passed to any calls to append() made since the BlobBuilder was created. This also resets the BlobBuilder so that the next call to append() is starting a new, empty blob.

getFile()

返回一个File对象.

File getFile(
  in DOMString name,
  [optional] in DOMString contentType
);

参数

name

文件名.

contentType 可选

设置返回的File对象中的数据的MIME类型.这个值将会成为返回的File对象的type属性的值.

返回值

一个File对象.

浏览器兼容性

注:BlobBuilder已被废弃

• 从Firefox 14开始,使用MozBlobBuilder会在Web控制台显示一条警告消息: MozBlobBuilder已被废弃,请使用Blob来代替.
• 从Firefox 18开始,MozBlobBuilder已被删除.
• WebKit has deprecated WebKitBlobBuilder and has made its support configurable. Currently Safari disables the feature in Nightly, so it will never likely to ship in the final version. On the other hand, Chrome, which has supported it since Chrome 8, still enables the feature. So Chrome might continue to support the feature. (See this WebKit changeset for details).

相关链接

• File API Specification: BlobBuilderED
• Blob
• File