Information Technology Reference
In-Depth Information
Web Programming Languages
Several programming languages are key to the Web.
Java
, for example, is an object-oriented
programming language from Sun Microsystems based on the C++ programming language,
which allows small programs, called
applets
, to be embedded within an HTML document.
When the user clicks the appropriate part of an HTML page to retrieve an applet from
a Web server, the applet is downloaded onto the client workstation, where it begins executing.
Unlike other programs, Java software can run on any type of computer. Programmers use
Java to make Web pages come alive, adding splashy graphics, animation, and real-time
updates.
In addition to Java, companies use a variety of other programming languages and tools
to develop Web sites. Software services delivered over the Web may run on the Web server,
delivering the results of the processing to the user, or may run directly on the client—the
user's PC. These two categories are commonly referred to as client-side and server-side soft-
ware. JavaScript, VBScript, and ActiveX (used with Internet Explorer) are Internet languages
used to develop Web pages and perform important functions, such as accepting user input.
Asynchronous JavaScript and XML (AJAX)
has become a popular programming language for
developing RIAs. Programs built with AJAX run smoothly on the client PC, occasionally
exchanging messages with the server.
Hypertext Preprocessor
, or
PHP
, is an open-source programming language. PHP code or
instructions can be embedded directly into HTML code. Unlike some other Internet lan-
guages, PHP can run on a Web server, with the results being transferred to a client computer.
PHP can be used on a variety of operating systems, including Microsoft Windows, Macintosh
OS X, HP-UX, and others. It can also be used with a variety of database management systems,
such as DB2, Oracle, Informix, MySQL, and many others. These characteristics—running
on different operating systems and database management systems, and being an open-source
language—make PHP popular with many Web developers. Perl is another popular server-
side programming language.
Adobe Flash
and
Microsoft Silverlight
provide development environments for creating rich
Web animation and interactive media. Both Flash and Silverlight require the user to install
a browser plug-in to run. Flash has become so common that popular browsers include it as
a standard feature. Microsoft Silverlight is a relatively new technology that is working to
become a competitor to Flash. Any Web site that you visit that provides sophisticated ani-
mation and interaction is probably created with Flash or Silverlight. Such pages often take
longer to load than standard HTML pages.
Java
An object-oriented programming
language from Sun Microsystems
based on C++ that allows small pro-
grams (applets) to be embedded
within an HTML document.
Developing Web Content
The art of Web design involves working within the technical limitations of the Web and
using a set of tools to make appealing designs. Popular tools for creating Web pages and
managing Web sites include Adobe Dreamweaver, Microsoft Expression Web, and Nvu. (See
Figure 7.8.) Today's Web development applications allow the user to create Web sites using
software that resembles a word processor. The software includes features that allow the de-
veloper to work directly with the HTML code or use autogenerated code. Web development
software also helps the designer keep track of all files in a Web site and the hyperlinks that
connect them.
After you create Web pages, your next step is to place, or publish, the content on a Web
server. Popular publishing options include using ISPs, free sites, and Web hosting. Web
hosting services provide space on their Web servers for people and businesses that don't have
the financial resources, time, or skills to host their own Web sites. A Web host can charge
$15 or more per month, depending on services. Some Web hosting sites include domain
name registration, Web authoring software, and activity reporting and monitoring of the
Web site. Some ISPs also provide limited Web space, typically 1 to 6 MB, as part of their
monthly fee. If more disk space is needed, additional fees are charged. Free sites offer limited
space for a Web site. In return, free sites often require the user to view advertising or agree
to other terms and conditions.
