[DougWebb]

The pre-XHR methods were super-clunky though. The technical contribution of XHR was to provide a standard and clean way of programatically sending HTTP requests in the background without refreshing the page. Without XHR or something like it, I don't think browser-side applications would have taken off the way they have.

It's a shame the Microsoft engineers hadn't thought of making websockets instead. Bi-directional communication would have been useful for the web-based version of Outlook they were supporting, and it would have become available to the rest of us much earlier.