Active Server Pages, better known by it's acronym, ASP, was the entry into the server-side scripting market for Microsoft, and is still in wide use today. The technology has gone through three major revisions since its inception.
ASP in of itself is not the name of the language in use behind the scenes. It is instead a service layer, under which lies the code choice of the developer. By default, this uses the Visual Basic language known as VBScript, and through its overwhelming use across the vast majority of ASP-based application, the term ASP often used when referencing VBScript.
Server side javascript can also be used in place of VBScript, although this practice is far less common, and Javascript is primarily known as a client-side application.
ASP has a long history and is wildy popular. As a language for beginning programmers, it is hard to beat.
DataSelect still supports programming ASP in some applications, especially where maintenance of existing ASP based websites is concerned. Clients such as Commercial Real Estate.com.au still have ASP in use. It is robust enough when used properly, and arguably in some instances there is little incentive to change to a more "modern" and feature rich scripting language.