Before XMLHttpRequest and the term AJAX existed, developers in 1995–1998 used browser scripting, CGI, forms, and clever page-integration tricks to simulate “dynamic” web apps. This chapter shows the web APIs and constraints that made XHR feel inevitable.
In the Web’s first years (1990–1994), HTTP was tiny, servers were simple, and “APIs” mostly meant speaking basic request/response over the network. Those constraints later produced AJAX—and eventually the Fetch API, which modernized the same fundamental idea.
XMLHttpRequest and AJAX didn’t arrive in the early 1990s—but the Web’s first HTTP interfaces did. This chapter explains the 1990–1994 foundations (URLs, HTTP requests, forms, and CGI) that made asynchronous web APIs inevitable.