标题：onIOError
类型
ActionScript 2.0 语言

介绍
当发生输入/输出错误时调用。
当上载或下载由于下列任何原因而失败时调用此侦听器：
当播放器正在读取、写入或传输文件时发生输入/输出错误。 
SWF 文件尝试将文件上载到要求身份验证（如用户名和密码）的服务器。在上载期间，Flash Player 不提供用户用于输入密码的方法。如果 SWF 文件尝试将文件上载到要求身份验证的服务器，则上载会失败。 
SWF 文件尝试在独立或外部播放器中从要求身份验证的服务器下载文件。在下载期间，独立和外部播放器不提供用户用于输入密码的方法。如果这些播放器中的 SWF 文件尝试从要求身份验证的服务器下载文件，则下载会失败。只有在 ActiveX 控件和浏览器插件播放器中，文件下载才有可能成功。 
传递到 upload() 中的 url 参数的值包含无效协议。有效协议包括 HTTP 和 HTTPS。 
重要说明：只有在浏览器中运行的 Flash 应用程序（也就是说使用浏览器插件或 ActiveX 控件的应用程序）可以提供对话框来提示用户输入用户名和密码以进行身份验证，然后只用于下载。对于使用插件或 ActiveX 控件进行的上载或者使用独立或外部播放器进行的上载和下载，文件传输会失败。
可用性
ActionScript 1.0；Flash Player 8
参数

fileRef:flash.net.FileReference - 启动操作的 FileReference 对象。
示例
下面的示例在触发 onIOError 事件时跟踪消息。为简单起见，此示例中不包含其它事件侦听器。 
import flash.net.FileReference;
var listener:Object = new Object();
listener.onIOError = function(file:FileReference):Void {
trace("onIOError");
}
var fileRef:FileReference = new FileReference();
fileRef.addListener(listener);
fileRef.download("http://www.macromedia.com/NonExistentFile.pdf", "NonExistentFile.pdf");
英语原文
E文好的可以看看原文
onIOError (FileReference.onIOError event listener)
onIOError = function(fileRef:FileReference) {}
Invoked when an input/output error occurs. 
This listener is invoked when the upload or download fails for any of the following reasons:
An input/output error occurs while the player is reading, writing, or transmitting the file. 
The SWF file tries to upload a file to a server that requires authentication, such as a user name and password. During upload, Flash Player does not provide a means for users to enter passwords. If a SWF file tries to upload a file to a server that requires authentication, the upload fails. 
The SWF file tries to download a file from a server that requires authentication, in the stand-alone or external player. During download, the stand-alone and external players do not provide a means for users to enter passwords. If a SWF file in these players tries to download a file from a server that requires authentication, the download fails. File download can succeed only in the ActiveX control and browser plug-in players. 
The value passed to the url parameter in upload() contains an invalid protocol. Valid protocols are HTTP and HTTPS. 
Important: Only Flash applications that are running in a browser -- that is, using the browser plug-in or ActiveX control -- can provide a dialog to prompt the user to enter a user name and password for authentication, and then only for downloads. For uploads that use the plug-in or ActiveX control, or that upload and download using either the standalone or external players, the file transfer fails.
Availability: ActionScript 1.0; Flash Player 8
Parameters
fileRef:flash.net.FileReference - The FileReference object that initiated the operation.
Example
The following example traces a message when the onIOError event is triggered. For simplicity, none of the other event listeners are included in this example. 
import flash.net.FileReference;
var listener:Object = new Object();
listener.onIOError = function(file:FileReference):Void {
trace("onIOError");
}
var fileRef:FileReference = new FileReference();
fileRef.addListener(listener);
fileRef.download("http://www.macromedia.com/NonExistentFile.pdf", "NonExistentFile.pdf");