如何AJAX文件上传工作？ [英] How ajax file uploads work?

问题描述

我们知道，JQuery的（或JavaScript）不能访问本地文件系统。那么，如何jQuery的各种AJAX文件上传插件实际工作，甚至显示进度条？

We know that, JQuery ( or javascript ) can not access local file system. So how does the various ajax file upload plugins of jquery actually work and even show the progress bar ?

我曾把使用Java小程序的文件上传，我可以做到这一点，因为在某种程度上，我能够读取使用小程序中的本地文件系统中的文件。因为我能读它，我把它一个100行的时间为100线多个部分，每个部分的发送成功使用 ajax.post ，操作进度条相应。

I once made an File Uploader using Java Applet and I could do it because somehow I was able to read the file from the local file system using applet. Because I was able to read it, I sent it a 100 lines at a time using ajax.post in multiple parts of 100 lines and as each of the part is successfully sent, manipulated the progress bar accordingly.

但是，当我们不能读取文件系统中的文件，然后怎么做的jQuery的AJAX插件显示进度条和上传文件异步？

But, when we can not read the file from file system, then how do the ajax plugins of jquery show the progress bar and upload the files asynchronously ?

推荐答案

通常情况下，有在服务器端的处理程序接受后，又接连处理报告任何上传的进度。

Typically, there is a handler on the server side accepting the post, and then another handler to report progress of any upload.

如果你举个例子框架来使用，我们可以给出一个更明确的答案。

If you give an example framework to use, we can give a more specific answer.

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