HTML and CSS Reference
In-Depth Information
and unscrambling to happen behind the scenes of the library Web page. After some
discussion, you decide that JavaScript is well suited to this task. You'll start on this project
by first finding out just what JavaScript is and how to use it.
Server-Side and Client-Side Programming
Programming on the Web comes in two types: server-side programming and client-side
programming. In server-side programming , a program is placed on the server that hosts
a Web site. The program is then used to modify the contents and structure of Web pages.
In some cases, users can interact with the program, requesting that specific information
be displayed on a page, but the interaction is done remotely from the user to the server.
See Figure 10-4.
Figure 10-4
server-side programming
3) a server-side program processes
the information and may send
additional feedback to the user
1) user retrieves Web
page from the server
2) information is sent to a
program running on the server
There are advantages and disadvantages to this approach. A program running on a
server can be connected to a database containing information not usually accessible to
end users, enabling them to perform tasks not available on their own computers. This
enables Web pages to support such features as online banking, credit card transactions,
and discussion groups. However, server-side programs use Web server resources, and in
some cases a server's system administrator might place limitations on access to server-side
programs to prevent users from continually accessing the server and potentially overload-
ing the system. If the system is overloaded, an end user might have to sit through long
delays as the server-side program handles multiple requests for information and action.
client-side programming solves many of these problems by running programs on the
user's own computer rather than remotely off the server. See Figure 10-5.
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