Prompt file download with XMLHttpRequest

Question

I\'m aware that jQuery\'s ajax method cannot handle downloads, and I do not want to add a jQuery plugin to do this.

I want to know how to send POST data with XMLHttp

Answer 1

XHR request will not trigger file download. I can't find explicit requirement, but W3C doc on XMLHttpRequest doesn't describe any special reaction on content-disposition=attachment responses either

You could download file by window.open() in separate tab, if it was not POST request. Here it was suggested to use hidden form with target=_blank

UPD: this answer is not accurate anymore since the introduction of Blob API. Please refer to Steven's answer for details.