Active Lisp Pages (ALP) is a server scripting environment for creating dynamic pages and interactive applications over the
Web. These pages can then be used in conjunction with any Web server, since the output of the ALP processor can be an HTML page.
An ALP script runs when a client (most likely a browser) requests an ALP file/page from the server. The server calls the ALP
engine, which reads through the requested file, generates a Lisp response function that will build the page (when run), and
compiles it. Finally, the ALP engine executes the response function (which will send the page back to the client). The
preliminary processing occurs only the first time the page is hit or, alternatively ALP pages can be preprocessed. Since the
server does the processing, there is no need to worry about whether a browser can process scripts. The server transmits standard
HTML to the browser. Server-side scripts cannot be copied, because only the result of the script is returned to the
browser. Since users cannot view the script commands that created the pages they are viewing, the system is secure.