on-the-fly

An expression used to describe the way a Web page is built and served to an end-user. Web sites built on-the-fly, including many news sites, contain dynamic content: information that changes frequently, sometimes as often as each time the page is requested by a user and loaded into a browser. The opposite of "dynamic" or "on-the-fly" Web pages are "static" or "flat" pages and files, which can only be altered by editing the original HTML file. That means the page has to be manually opened in an HTML or text editor and changed by the author. Producing pages on-the-fly is usually achieved with technologies such as Cold Fusion, Active Server Pages, or another kind of database-driven technology.