FileError

Obsolete
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

Represents an error that occurs while using the FileReader 接口。

注意: This interface is obsolete per the latest specification. Use the new DOM4 DOMError interface instead.

In the 文件系统 API FileError represents error conditions that you might encounter while accessing the file system using the asynchronous API. It extends the FileError interface described in File Writer and adds several new error codes.

FileError objects are passed to error callbacks. The objects have a code that shows the type of error that occurred.

Best practices

Most people don't read the page on errors and exceptions unless they're stumped. So the following are a few tips that could help you avoid some pitfalls.

Error callbacks are not optional for your sanity

Although error callbacks are optional, you should include them in the arguments of the methods for the sake of the sanity of your users. A web app could fail for various reasons, so you don't want to spend the rest of your day guessing what's going on and going through maddening troubleshooting.

Don't run your app from file://

For security reasons, browsers do not allow you to run your app from file:// . In fact, many of the powerful storage APIs (such as File System, BlobBuilder, and FileReader) throw errors if you run the app locally from file:// . When you're just testing your app, and you don't want to set up a web server, you can bypass the security restriction on Chrome. Just start Chrome with the --allow-file-access-from-files flag. Use the flag only for testing purposes.

属性

属性 Type 描述
code unsigned short The most appropriate error code for the condition. See Error codes for possible values.

Error codes

注意: Do not rely on the numeric values of the constants, which might change as the specifications continue to change. Use the constant names instead.
常量 描述
ENCODING_ERR 5 The URL is malformed. Make sure that the URL is complete and valid.
INVALID_MODIFICATION_ERR 9 The modification requested is not allowed. For example, the app might be trying to move a directory into its own child or moving a file into its parent directory without changing its name.
INVALID_STATE_ERR 7 The operation cannot be performed on the current state of the interface object. For example, the state that was cached in an interface object has changed since it was last read from disk.
NO_MODIFICATION_ALLOWED_ERR 6 The state of the underlying file system prevents any writing to a file or a directory.
NOT_FOUND_ERR 1 A required file or directory could not be found at the time an operation was processed. For example, a file did not exist but was being opened.
NOT_READABLE_ERR 4 The file or directory cannot be read, typically due to permission problems that occur after a reference to a file has been acquired (for example, the file or directory is concurrently locked by another application).
PATH_EXISTS_ERR 12 The file or directory with the same path already exists.
QUOTA_EXCEEDED_ERR 10 Either there's not enough remaining storage space or the storage quota was reached and the user declined to give more space to the database. To ask for more storage, see Managing HTML5 Offline Storage .
SECURITY_ERR 2

Access to the files were denied for one of the following reasons:

  • The files might be unsafe for access within a Web application.
  • Too many calls are being made on file resources.
  • Other unspecified security error code or situations.
TYPE_MISMATCH_ERR 11 The app looked up an entry, but the entry found is of the wrong type. For example, the app is asking for a directory, when the entry is really a file.

浏览器兼容性

更新 GitHub 上的兼容性数据
Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
FileError
弃用 非标
Chrome 13 — 53
Prefixed
不支持 13 — 53
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge ? Firefox ? — 13
不支持 ? — 13
FileError interface has been removed starting with Firefox 13.0. Instead the more general DOMError interface is used and returned by FileReader.error .
IE No Opera ? — 40 Safari No WebView Android ? — 53
Prefixed
不支持 ? — 53
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 18 — 53
Prefixed
不支持 18 — 53
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android ? — 14
不支持 ? — 14
FileError interface has been removed starting with Firefox 13.0. Instead the more general DOMError interface is used and returned by FileReader.error .
Opera Android ? — 41 Safari iOS No Samsung Internet Android 1.0 — 6.0
Prefixed
不支持 1.0 — 6.0
Prefixed
Prefixed Implemented with the vendor prefix: webkit

图例

不支持
不支持
兼容性未知
兼容性未知
非标。预期跨浏览器支持较差。
非标。预期跨浏览器支持较差。
弃用。不要用于新网站。
弃用。不要用于新网站。
见实现注意事项。
要求使用供应商前缀或不同名称。
要求使用供应商前缀或不同名称。

另请参阅