I think you missed the "well" in my quote (no one said it was hypothetical). Naturally the XMLHttpRequest / AJAX was used with XML first. Microsoft were the one

I think you missed the "well" in my quote (no one said it was hypothetical). Naturally the XMLHttpRequest / AJAX was used with XML first. Microsoft were the ones to introduce it to do exactly that; work with their exchange server's XML. This is why I said "well". XML isn't a perfect fit into JavaScript's existing objects. It's awkward. Mozilla, imperfectly, copied the interface Microsoft came up with to have a sort of standard and 4 months after that Crockford started using JSON[1]. I don't see much history of applications beyond Microsoft's and a few edge cases that really used XML here; most of what I can find online had a lot of people's first usage of AJAX with JSON or plain text. But I'll admit it's very difficult to find solid data. But ultimately XMLHttpRequest came out, in its very first ActiveX form in IE, in March 1999 and Crockford started playing with JSON in April 2001. Wikipedia claims XMLHttpRequest didn't become a de facto standard until 2004 when other browsers started adopting it[2] so I'm not convinced it was used for very much XML to begin with. [1] https://www.youtube.com/watch?v=-C-JoyNuQJs https://www.youtube.com/watch?v=-C-JoyNuQJs [2] https://en.wikipedia.org/wiki/XMLHttpRequest https://en.wikipedia.org/wiki/XMLHttpRequest