If there is one technology that caught up literally overnight and has affected more users than any other it is the Web. Lie World ·Wide Web is the set of all Web sites and the documents they can provide to clients. The computers that host Web sites are called servers their service is to provide the documents that clients request. Clients are the millions of personal computers connected to the Internet. To exploit the Web, all you need is a browser such as Internet explorer that can request documents and render them on the client computer.
I assume that most of you are familiar with the Web. This chapter is a compendium of information on how to apply the knowledge you acquired in previous chapters to the Web. Or to use a popular term leverage your knowledge of Visual Basic by applying it to the Web. To do so you need a basic understanding of HTML (HyperText Markup Language)’ the language used to build Web documents and VB Script the language for programming the Web client and the Web server.
The first section of this chapter describes the protocols used on the Web and on the Internet and then I briefly discuss HTML tags and show you how to use HTML to build simple hyperlinked documents (static Web pages). Next we look at how to activate Web pages by scripting them with VBScript and adding ActiveX controls to them. In short you will learn how to turn a static Web page into an interactive application that can be executed over the Internet in the browser’s window. We will also build Web pages that use the custom ActiveX
controls we developed in the last chapter.
I will also discuss the basics of developing Dvnamic HTML page. DHTML is the latest trend in Web page design which bikes HTML to a new level allowing Web authors to develop HTML applications that behave like desktop applications with rich multimedia elements. DHTML is a huge topic to discuss in detail so I will just demonstrate the principles of DHTML. Since I can’t cover everything you need to know about the Web I’ll focus on a few topics that will help you understand how the Web works and how to develop Web pages that behave like applications and then I’ll discuss the role of VBScript in programming Web pages. In the following chapters you’ll find more specific information on how to combine Visual Basic and Web authoring techniques both on the Web and in your Visual Basic applications. As you will see it’s possible to display HTML pages on VB Forms and exploit the hyperlinked model of the Web from within your applications.
The Web Also Means Intranets
“The information in this chapter isn’t addressed only to those of you who are going to publish documents on the Internet. You will also find it useful in building intranet applications.
The Web caught on so rapidly because it’s really simple to use. It has even become an integral part of the operating system itself, and the Windows 98 Desktop is based on the hypertext model.
If Web technology simplified a chaotic structure such as the Internet why not also use it . on local networks Indeed many local area networks are designed as miniature.An intranet or corporate internet is a local area network that uses Internet technology. On an intranet you can exploit the Web model to simplify operations without the security issues you face on the internet or the limitations imposed by connecting computers with modems.
An intranet is also a network of computers operating on the TCP/IP protocol but it is not ” global Intranets are restricted to the users of a corporation, a university or some other organization and they are not accessible by the outside world Unlike the World Wide Web intranets don’t have more than one server. This machine supplies all the documents requested by the clients Many corporations use intranets to provide information to their employees and they run another Web size for external users. The reason for building corporate internet is to exploit the technology that made the Web so popular. So intranet is not that it uses much as HTTP(Hyper Text Transfer Protocol).
