Let's go even further back in time than Ajax. The need for loading content on various regions of a page without reloading the full window has been around for a long time. Who remembers framesets? They let you define regions in a page and load different HTML documents into them without reloading everything. This was basically doing SPAs before SPAs were a thing. A testament to the enduring need for partial page updates. An early built-in solution for it, which goes back to Netscape 2 and IE3, and which was part of the HTML4 spec. But which didn't survive the passing of time, due to multiple issues like back/forward navigation was broken, bookmarking was broken too, search engines indexing was a disaster, etc.