2.0.0- Server-Side Scripting and Client-Side Scripting

Server-Side Scripting and
Client-Side Scripting

In the first chapter we introduced Active Server Pages, and we demonstrated how you'd go about setting up your web server and getting Active Server Pages working. We learned that ASP web pages are a mixture of plain text, HTML code and ASP script. We also learned that ASP pages are stored as .asp files on the server – when a user requests an ASP page, the ASP script contained in the .asp file is processed on the server before the resulting HTML is sent to the browser.

What we haven't done is discuss the workings of ASP in any detail, or how web servers interpret ASP. In this chapter, we aim to reinforce your understanding of the workings of ASP, by describing three different models. First, we'll look at how information is transmitted between the browser and web server; second, we'll examine how the web server handles web page requests; and third, we'll see how the ASP script engine on your web server actually handles lines of ASP script code.

We'll also look at the two ways at which script can be handled, either on the web server or the browser; and we will explain why ASP script can only be handled on the server. Once we've looked at how ASP works, we'll look in greater depth at ASP itself and break it up into its individual objects. So we'll be explaining the following:

• How do web servers work? What do they do?
• What is a web application?
• What is a request? What is a response? And how do they relate to the roles of the browser and web server?
• What's the difference between server-side scripting and client-side scripting?
• What is the ASP object model?
• What other methods, apart from ASP, can be used to generate dynamic web pages?

This is the second and last of our foundation chapters. We'll be writing some ASP pages in this chapter, but they'll be mainly for illustrative purposes – we'll avoid in-depth discussions of syntax and programming technique until we've laid down the concepts of ASP programming. We'll begin to work on ASP syntax and techniques in Chapter 3.