XMLHttpRequest.multipart

Is a boolean. This Gecko-only feature was removed in Firefox/Gecko 22. Please use Server-Sent Events, Web Sockets, or responseText from progress events instead.

Indicates whether or not the response is expected to be a stream of possibly multiple XML documents. If set to true, the content type of the initial response must be multipart/x-mixed-replace or an error will occur. All requests must be asynchronous.

This enables support for server push; for each XML document that's written to this request, a new XML DOM document is created and the onload handler is called between documents.