If a user is burdened with a slow Internet connection, he will find that it takes time for a web page to be displayed (downloaded) to his client computer. Now there's a way to arrange it so that only the first page of his requested web site would take a long time to be downloaded; the rest of the pages would come very fast. This can be a real advantage. If you want to learn more about this approach, referred to as Active Client Pages, keep reading.
Active Client Pages: Chrys`s Approach - Active Server Pages and Active Client Pages (Page 2 of 4 )
Many professional web sites use server-side applications like PHP, ASP, JSP etc. to generate their pages. All of these systems produce HTML pages at the server, based on data (or some non-standard information) at the server.
Active Client Pages, on the other hand, produce HTML pages in the browser at the client, but still use data or information stored at the server. Well, with Active Client Pages, the very first page may be produced at the server. In practice, the rest of the pages, produced at the client, are actually downloaded from the server in advance as texts (strings with escaped entities).
Definition of Active Client Pages
We have enough information now to understand the definition of Active Client Pages. The definition I am giving you here is my definition. It is not what Vlad or Chuck has given.
Active Client Pages is defined as the production of HTML pages at the client computer by the browser using web technology.
The data or information for the HTML pages resides on the server. You need a client script language, such as JavaScript, to produce the HTML pages at the client.
I use JavaScript in my articles. Let me now welcome you to the new exciting world of Active Client Pages.
JavaScript 
Active Client Pages: Summary of the Document Phase of Chrys`s Approach
