1996: Internet Explorer 3This version of the browser, introduced in 1997, was the first browser to implement CSS (Cascading Style Sheets). Yes, you’re reading that correctly—in fact, it introduced many new features like Java applets and sadly, ActiveX controls.
1997: Internet Explorer 4IE4 introduced a blazing fast (at the time) rendering engine as an embeddable component that could be used in other applications—this was a lot more important than people realize. This version also introduced Dynamic HTML, which allows web pages to dynamically change the page using JavaScript, and added Active Desktop integration.
Even more weird? Seems like nobody remembers this anymore, but IE4 was actually cross-platform—you could install it on Mac OS, Solaris, and HP-UX—and by the time IE5 was released, IE4 had reached a 60% market share.
1999: Internet Explorer 5.xMicrosoft invented Ajax. Wait… what? That’s right, it was this version of IE that introduced the XMLHttpRequest feature in JavaScript, which forms the underlying technology behind every web application you’re using today—you know, like Gmail. Of course, the term “Ajax” wasn’t actually coined until years later by somebody other than Microsoft, but this release supported everything required to make it work.