A Web Development Primer
Java was developed by Sun Microsystems and is a programming language with complete functionality similar to that of C++. At this point, Java's niche is on the World Wide Web. Probably the most important things that Java brings to the Web are the capacity for more interactivity on the Internet through multimedia and animation. Most modern browsers have support for Java.
Flash and ActionScript
Macromedia Flash is an authoring tool that can create a special type of file called "Flash movie" and uses".SWF" as extension. You can see this type of movie all over the Internet, and sometimes you don’t even recognize it as Flash movie because it looks like a normal animated banner. Flash supports animation and sound. If you have created your graphics in Flash, you will be able to move these on the "stage." As in a real film, you put your graphics on the stage and tell the program if and when they should move. You have a "timeline" where you do control the timing of the animation, and you have "keyframes" where you do control the position of the objects on the stage. Flash contains a powerful programming language called "ActionScript" that is capable of doing much more. With ActionScript you can build movies which can interact with the viewer. This can be convenient if you want to build a quiz, a game or a shopping cart in Flash. If you can use an additional script language on your web server, you are even able to build complex database applications on the Web.
Server Side Technologies
Server-side technologies are the way that you can take your Web site to the next level. Server-side technologies can be regarded as those technologies that enable you to dynamically generate HTML and CSS. Take Amazon.com for example. Amazon won't make separate web page for each their product, but if you have a close look to at Amazon.com's page, you'll notice that it has many other contents that are presented depending on the product you are viewing like ‘related products,’ ‘product review,’ etc. You'll notice that you can post a product's review on the site, and it will appear instantly. Do you think that there's someone behind the screen to paste your review and save it as an HTML page for you to view on your browser?! No!
This is where the wonder and magic of server-side technologies comes into play. The task of generating HTML pages is left to that of the server. The instructions needed to decide on what content are to be included in the HTML page is made possible through CGI or server-scripting languages which will be discussed later in this article.
To thoroughly understand the significance of server-side programming languages, it's appropriate to examine the weakness of HTML. HTML produces static web pages, or web pages that never automatically change. To alter any static page, you must make it happen.
A server-side document is written in any text application like Notepad, and is uploaded to the web server. The document containing this script is saved on the web server. When someone makes a request for a page from his web browser the script file is sent to the appropriate interpreter, the code is executed and HTML is automatically generated from the executed code. The resulting document is pure HTML, and the user requesting the document will never see the actual scripting language.
By making use of server-side technologies, highly interactive web applications can be built, and customized to the user preferences. Web applications can be made to interact with databases or other files, to store, retrieve and perform other data manipulation tasks. More examples and applications will be given throughout this section.
The Common Gateway Interface (CGI) is used to execute external applications on Web Servers. Suppose you have an HTML file on your server, and someone makes a request to access that file from his browser. Since HTML is static, it won’t change, and its content will always be the same. Now, let's say that you have a CGI program on your web server; it is executed in real-time, so that it can output dynamic information upon user request. A CGI program can be written in any language that allows it to be executed on the system, such as: C, Perl, TCL, Visual Basic, etc… CGI is losing popularity these days due to the rise of server-side scripting languages which is explained below.
Server Side Scripting Language
Server-side scripting language involves PHP, ASP, and JSP. The role of server-side scripting language is the same as CGI but with server based scripting, instead of the code outputting the lines of the Web page; the Web page itself contains the code. Furthermore, the server usually has the interpreter built-in, so it can serve up lots of requests with lower resource requirements.
ASP stands for Active Server Pages and is a division of Active Platform concept of Microsoft Technologies. To get a better understanding of what ASP is and how it works, let’s break the terms:
Active – means that the HTML is created dynamically by your ASP pages.
Server – refers to the fact that there is a computer involved in the process, thus it is a server-side technology. The resulting file is pure HTML.
Pages – means that the HTML file is sent to the browser which displays the HTML content of the ASP file in its window.
ASP is great for creating almost any kind of dynamic web content from discussion groups to shopping carts. ASP is ideal for simplifying tasks that would otherwise be very cumbersome or impossible in HTML.