Scripting languages
Summary Description Want to add flashy features
to a Web page or adapt software to your needs? Newswire's 5
Minute Guides takes a look at scripting.
Author
Publication
Roullas Top10 Simon Vandore
Newswire
No
Editorial InformationArticle Location
http://www.newswire.com.au/0006/5mg26.htm
Article Topic 5 Minute Guides
Story Order
Story Group 000625
Post Date 26/06/2000 09:32 AM Status Posted Entered by Simon
Vandore on 20/06/2000 09:20 PM
ImagesLead Picture
Heading Image
Content
Introduction
Want to add flashy features to a Web page or adapt software to
your needs? 5 Minute Guides takes a look at scripting.
Body
Scripting languages? I'm not an actor!
In computing terms, a script is a set of orders to be carried out
by a program. Scripts are separate files to which a program
refers as required.
For example, when your modem dials an ISP and establishes a
connection, Windows can use a script that tells it how to react
to the queries coming down the telephone line. The script might
tell the modem software that if the letters 'Password?' arrive
from the remote connection, the software should wait two seconds,
then transmit the password and a carriage return. Another type of
script might instruct Web server software on how to handle the
output it receives from an online form, telling it to email the
data to the shop owner or append the data to a separate Web page.
Scripting languages are similar to programming languages, but
never quite as complex or powerful. However, this makes them much
easier to use -- almost anyone can learn a bit of scripting! The
most advanced scripting languages can often be used in place of
pure programming techniques, particularly in adding functions to
existing programs. The downside is that scripts run more slowly
than programs because they don't deal directly with the
processor.
What are some of the most common scripting languages?
On the Web, scripts are traditionally run on the server, but it's
often appropriate to pass them to the Web browser software on the
client. On the server side a scripting language called Perl,
loved by many Unix users, is usually used for CGI (common gateway
interface) scripting, the original means of adding non-HTML
functions to a Web page. There are a variety of client-side
scripting languages, such as JavaScript, VBScript and PHP.
After SunSoft introduced its Java programming language, Netscape
adopted some of the ideas for JavaScript, a client-side scripting
language which can be embedded in Web pages and run by most
modern Web browsers (even those without a Java Virtual Machine).
JavaScript also has a few things in common with Perl, meaning it
was relatively easy for practised CGI hackers to adopt. Many of
the flashy effects and interactive parts of Web pages are created
with JavaScript.
Microsoft developed its own Java-related scripting language,
dubbed JScript, but JavaScript remains more popular. Microsoft
also introduced VBScript, derived from its Visual Basic
programming language. However, only the Internet Explorer browser
and the various Windows operating systems support VBScript. Files
written in this language are given the extension '.vbs', just
like the recent love bug virus!
PHP, which originally stood for Personal Home Page Tools, exists
on both client-side and server side. Its scripts are embedded in
HTML pages, but interpreter software which responds to PHP output
is also run on the server. Pages using PHP often have a '.php',
'.php3' or even '.php4' file extension. It's a useful language
for generating Web pages on the fly, based on input from the
user, such as news pages or online diaries which can be updated
using Web forms.
Sun has a scripting language used with its Solaris operating
system called Tcl, and IBM has a long-standing language developed
for its mainframes called REXX.
Are there any standards for scripting?
The European Computer Maufacturers Association (ECMA) managed to
get Microsoft and Netscape to cooperate on a standard for
scripting languages called ECMA-262. Both JavaScript and JScript
are closely related to ECMA-262.
Sometimes a Web page has the file extension '.asp' instead of
'.htm' or '.html'. This is a designation introduced by
Microsoft's Internet Information Server software and stands for
Active Server Page (ASP), meaning a script is included somewhere
in the HTML. Generally ASP uses VBScript or JScript. However,
this is only really a 'standard' for servers running Windows or
Windows NT. Administrators of Linux-based Web servers often use
PHP to achieve the same effect.
Beyond standards, many proprietary scripting languages exist for
specific pieces of software. Games such as the Unreal and Quake
series feature scripting tools for creating add-ons. In the world
of Internet Relay Chat (IRC), 'bots' which might act like
personalised robotic helpers, are actually scripts written to
respond to prompts in IRC text output.
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Bulletin Summary5 Minute Guides: Scripting languages
Want to add flashy features to a Web page or adapt software to
your needs? Newswire's 5 Minute Guides takes a look at scripting.
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5 Minute Guides: Scripting languages
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