在此页

• 摘要
• 句法
• 范例
• 规范
• 另请参阅
• 相关话题

非标
此特征是非标准的，且不在标准轨道中。不要在面向 Web 的生产站点中使用它：它不适用于每个用户。实现之间可能存在大的不兼容性，且行为将来可能改变。

摘要

This property specifies a callback function to be run repeatedly while the operation represented by a FileRequest object is in progress.

句法

instanceOfFileRequest.onprogress = function;
					

Where instanceOfFileRequest 是 FileRequest object and function is the JavaScript function to execute.

Each time the function callback is called, it gets an object as its first parameter. Those objects contain two properties:

loaded

A number representing the current amount of bytes processed by the operation.

total

A number representing the total amount of bytes that will be processed by the operation.

范例

// Assuming 'request' which is a FileRequest object
request.onprogress = function (status) {
  var progress = document.querySelector('progress');
  progress.value = status.loaded;
  progress.max   = status.total;
}
					

规范

Not part of any current specification.

另请参阅

• DOMRequest
• LockedFile

元数据

• 最后修改： 2019 年 3 月 23 日

相关话题

1. 文件和目录条目 API
2. FileRequest
3. 特性

   1. lockedFile
   2. onprogress
4. 事件

   1. error
   2. writeend
5. 文件系统 API 相关页面

   1. FileError
   2. FileException
   3. FileHandle
   4. FileSystem
   5. FileSystemDirectoryEntry
   6. FileSystemDirectoryEntrySync
   7. FileSystemDirectoryReader
   8. FileSystemDirectoryReaderSync
   9. FileSystemEntry
   10. FileSystemEntrySync
   11. FileSystemFileEntry
   12. FileSystemFileEntrySync
   13. FileSystemFlags
   14. FileSystemSync
   15. HTMLInputElement
   16. LocalFileSystem
   17. LocalFileSystemSync
   18. LockedFile
   19. 元数据
   20. Window.requestFileSystem()
   21. Window.resolveLocalFileSystemURL()
   22. WorkerGlobalScope.requestFileSystemSync()