[mibbit]

XHR was introduced many years after js was extremely popular. Also XHR doesn't add anything technically. The same thing can be achieved with dynamically adding <script> tags, or using an iframe, or a number of other methods.

The introduction of the buzzword 'ajax' certainly popularized what people had already been doing for years though.

[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.

[flomo]

And XMLHttpRequest was the replacement for an earlier applet-based method called 'Remote Scripting', which was pulled when MS lost the Java lawsuit. (And contrary to what DougWebb said, it worked pretty well.)

Remote Scripting itself was a copy of an IBM applet which Netscape pushed in the v4 timeframe (although practically, NS4 was too unstable to do any real dynamic html.)

So it really was the "AJAX" branding effort that got devs to notice what had been under their noses for some time.

("MSRS" now stands for something else entirely, but here's an old article discussing pre-historic AJAX techniques: http://www.ibm.com/developerworks/web/library/wa-resc/ )