如何使用AJAX/jQuery创建一个进度条来下载XML内容?

I apologize if this is a rather simple answer, but I've been stuck on it for a while. Currently I have an XML file where users can add images, audio files, and text in a multitude of ways. In case the file becomes large, I'd like for the page to require a progress bar. I apologize if this is a rather simple answer,