Page 15 - DCAP604_MODERN_WEB_PROGRAMMING_TOOLS_AND_TECHNIQUES_I

Unit 1: The .Net Framework

5. They are portable and possess the capability to generate dynamic and user-based content Notes
(e.g. displaying transaction information of credit card or debit card depending on user’s
choice).

1.2.2 Types of Server-side Programs

Various types of server-side programs are:
1. Active Server Pages (ASP)
2. Java Servlets

3. Java Server Pages (JSPs)
4. Enterprise Java Beans (EJBs)
5. PHP

1.3 Client-side Programming

At the same time that server-side web development was moving through an alphabet soup of
technologies, a new type of programming was gaining popularity. Developers began to
experiment with the different ways they could enhance web pages by embedding miniature
applets built with JavaScript, ActiveX, Java, and Flash into web pages. These client-side
technologies don’t involve any server processing. Instead, the complete application is downloaded
to the client browser, which executes it locally.
The greatest problem with client-side technologies is that they aren’t supported equally by all
browsers and operating systems. One of the reasons that web development is so popular in the
first place is because web applications don’t require setup CDs, downloads, and other tedious
(and error-prone) deployment steps. Instead, a web application can be used on any computer
that has Internet access. But when developers use client-side technologies, they encounter a few
familiar headaches. Suddenly, cross-browser compatibility becomes a problem. Developers are
forced to test their websites with different operating systems and browsers, and they might
even need to distribute browser updates to their clients. In other words, the client-side model
sacrifices some of the most important benefits of web development.
For that reason, ASP.NET is designed as a server-side technology. All ASP.NET code executes on
the server. When the code is finished executing, the user receives an ordinary HTML page, which
can be viewed in any browser. Figure 1.5 shows the difference between the server-side and the
client-side model.
These are some other reasons for avoiding client-side programming:
1. Isolation: Client-side code can’t access server-side resources. For example, a client-side
application has no easy way to read a file or interact with a database on the server (at least
not without running into problems with security and browser compatibility).

2. Security: End users can view client-side code. And once malicious users understand how
an application works, they can often tamper with it.
3. Thin clients: As the Internet continues to evolve, web-enabled devices such as mobile
phones, palmtop computers, and PDAs (personal digital assistants) are appearing. These
devices can communicate with web servers, but they don’t support all the features of a
traditional browser. Thin clients can use server-based web applications, but they won’t
support client-side features such as JavaScript.

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