The enterprise software that enabled dynamic websites

Friday, May 06, 2022

Anyone who claims to be familiar with Web history should know that Ajax was the enabler for modern client-side web applications. It enabled the quick feedback to user interactions, brought to the mainstream through services like Gmail and Google Maps1.

The secret sauce behind Ajax was XMLHttpRequest which was introduced in Internet Explorer (!) back in 1999 (!!). Yes, Microsoft was the driving force behind the technology that enabled dynamic web pages later brought to the masses through Javascript libraries like jQuery. So, why the heck did Microsoft develop XMLHttpRequest?

Outlook Web Access.

This much I knew before. And I’ve seen and used OWA deployed in a few occasions. However, while watching a YouTube video by RetroSpector78 on Microsoft Exchange Server 5.5, I was in for a surprise. Jumping to 13:10 of that video, we see that OWA is an option when installing Exchange Server. That’s when I realized…

XMLHttpRequest was a facility developed for Microsoft’s enterprise software to enable a desktop application-like experience2 in a web browser.

Let that sink in for a second. 😉

OK, the full story goes that the implementation in IE was exposed through ActiveX, so it could be considered a proprietary technology at the time. Then, Mozilla came along later to implement XMLHttpRequest to be accessible through Javascript, which other browsers followed suit, and the rest is history.


  1. Those applications felt revolutionary at the time (circa 2004) when practically every user interaction with a website was through page loads upon page loads. 

  2. … and that shouldn’t come as a surprise considering Microsoft was still very invested in the desktop computing experience at the time.