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Web browsing (navigation) started with the classical hypertext navigation, occurring among “Static” documents. Hypertext is text, displayed on a computer, with references (hyperlinks, links) to other text that the reader can immediately follow, usually by a mouse click or keypress sequence. Apart from running text, hypertext may contain tables, images and other presentational devices. Any of these can be hyperlinks; other means of interaction may also be present, e.g. a bubble with text may appear when the mouse hovers somewhere, a video clip may be started and stopped, or a form may be filled out and submitted. The most extensive example of hypertext today is the World Wide Web. For the “web users”, this experience is reproduced using static web pages, which are web pages that always displays the same information for all users, from all contexts.

Advantages

• Quick and easy to put together, even by someone who doesn't have much experience. • Ideal for demonstrating how a site will look. • Cache friendly, one copy can be shown to many people.

Disadvantages

• Difficult to maintain when a site gets large. • Difficult to keep consistent and up to date. • Offers little visitor personalization (all would have to be client side).

However, web navigation can also provide an "interactive experience" that is termed "dynamic." Content (text, images, form fields, etc.) on a web page can change, in response to different contexts or conditions. There are two ways to create this kind of interactivity:

1. Using client-side scripting to change interface behaviors within a specific web page, in response to mouse or keyboard actions or at specified timing events. In this case the dynamic behavior occurs within the presentation.

To adhere to this first definition, web pages must use presentation technology called, in a broader sense, rich interfaced pages. Client-side scripting languages like JavaScript or ActionScript, used for Dynamic HTML (DHTML) and Flash technologies respectively, are frequently used to orchestrate media types (sound, animations, changing text, etc.) of the presentation. The scripting also allows use of remote scripting, a technique by which the DHTML page requests additional information from a server, using a hidden Frame, , or a .

2. Using server-side scripting to change the supplied page source between pages, adjusting the sequence or reload of the web pages or web content supplied to the browser. Server responses may be determined by such conditions as data in a posted HTML form, parameters in the URL, the type of browser being used, the passage of time, or a database or server state. Web pages that adhere to the second definition are often created with the help of server-side languages such as PHP, Perl, ASP or ASP.NET, JSP, and other languages. These server-side languages typically use the (CGI) to produce dynamic web pages. These kinds of pages can also use, on client-side, the first kind (DHTML, etc.).

The result of either technique is described as a dynamic web page, and both may be used simultaneously.

In computing, a hyperlink, usually shortened to link, is a directly followable reference within a hypertext document.

The area from which the hyperlink can be activated is called its anchor; its target is what the link points to, which may be another location within the same page or document, another page or document, or a specific location within another page or document; this depends on the type of hypertext.

To insert a hyperlink to another place is often simply called to "link". Hypertext (meaning "more than just" text) is a form of text typically published on websites that provides a richer functionality than simple text documents by enabling the reader to explore interesting links to other web pages linked to specific words or images within the page. Typically the link anchor will be descriptive of to the target's content, for example Wikipedia home page, but badly designed or malicious sites may use obscure links or obfuscated links which make it hard to work out where the link will take you.

A Dynamic Web Page is a web page that a user can request information/data to its own need and the page to be able to respond to the request and display the exact content of its request.

Data flow of a typical dynamic website

Tools needed in terms of software and knowledge needed for learning PHP

Difference between Scripting and Viewing in a browser

DATA FLOW

Lets take a look at a simple explanation of how data moves around with the dynamic website and how this differs from the static web pages.

The different elements to look at, are • The User’s Machine connected to the Internet and • The Server.

The request from a user machine for a webpage will be served through the Internet by a Server.

In this case the Server is an , which differs from a standard Web Server, in that, Web Server will only serve whenever it is ask for, and the data stored on a Web Server is all completely pre packaged as HTML pages or even if the data seems more complex and dynamic, for instance if it serves Java script or Flash movies. All of that is essentially static, meaning that, the user simply requests the particular page and gets the content in the form base arranged on the server.

The Application Server however can run a script when that's requested by the user and through the input that the user has returned to the Application Server it can make dynamic and more intelligent choices about the kind of content that the user wants to see. It can work in conjunction with a Database Server and although these are usually separate its quite possible that they are actually on one machine with an Application and Database Server effectively in the same box, but they are different concepts so even if they are physically together is best to look at them as two separate entities. So what happens basically, when the user types in the URL of whatever page they call in of the Internet is that the Request is passed to the Application server and thats the point that which the PHP comes in. The scripts that we run on Application server to allow the content to be served in a dynamic way based on the users choices and what we know about the user are written in a variety of different scripts. Obvious examples are MS Active serverpages which use vv script and j script. Other examples are be Perl or Java serverpages or Coldfussion. We are looking at PHP and all of these tools the way they do things some areas are better than others they all fulfill the same kind of purpose, running a script on the application server. So this is where the technology that we are gone a be looking at, through out this title, PHP, comes in, the script that are run on the Application server. These scripts may then request, based on the information that they pass on by the user, information from a database server, and the database server sends back information to the script, which then serves the data wrap in an acceptable form to be handed back to the user. Now we will be looking at serving pure html. It perfectly possible to serve other kinds of technology, such us Java script or Clientside scripting through php. But typically we are gone a be will be serving up html. It is also possible to pass information to a client site application, for instance with macromedia Flash. Sending information from php to Flash. However and its simplest form php will serve html which is readable in any browser on the users machine. A distinction should be made here, is between server side scripting such as php or any of the other technologies and client side scripting such as java script ……… or Flash movies. These are client side scripts or applets and these should not be confused with the job that is done by php which is a server side technology. So the content is returned by the internet to the user’s machine based on their choices and the structure that we set up in our php scripts. This basically how the dynamic web works