| Cascading Style Sheets
|
CSS A mechanism that allows authors and readers
to attach the same style (e.g. fonts, colors and spacing) to
multiple HTML documents.
The CSS language is human readable and writable, and expresses style
in common desktop publishing terminology.
One of the fundamental features of CSS is that style sheets cascade;
authors can attach a preferred style sheet, while the reader may have
a personal style sheet to adjust for human or technological handicaps.
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| CDF
|
Channel Definition Format (CDF) is the proposed open industry standard
for data definition of content to be pushed across the Internet. CDF
is an application of XML, which is a subset of SGML, that
specifies how data can be automatically broadcast from any web
server to compatible receiver programs on client computers
requesting such broadcasts.
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| CGI
|
Common Gateway Interface A convention for servers to
communicate with local applications.
Gateways are programs which handle information requests and return the
appropriate document or generate a document on the fly.
Servers can display information which is not
readable by the client, such as a database,
and act as a "mediator" between the two to
produce something which browsers can display.
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| CGI input
|
Data generated by environment variables and
standard input (when using the POST method).
These environment variables are set when the server
executes the gateway program.
For example, the environment variable QUERY_STRING
represents a string that follows the question mark in the URL.
This information could be added either by an isindex document,
or by a form using the GET method.
In the POST method, form data are read from standard input.
Since the server does send an EOF at the end of the data, the
environment variable CONTENT_LENGTH is included to determine how
much data to read from stdin.
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| CGI Libraries
|
A collection of libraries used for writing scripts.
cgi-lib.pl is simple Perl library which is designed to make writing
CGI scripts in Perl easy.
The CGI.pm Perl 5 library uses objects to create Web fill-out
forms on the fly and to parse their contents.
It is similar to cgi-lib.pl in some respects. It provides a simple
interface for parsing and interpreting query strings passed to CGI
scripts. However, it also offers a rich set of functions for
creating fill-out forms. Instead of remembering the syntax for HTML
form elements, you just make a series of Perl function calls.
An important fringe benefit of this is that the value of the previous
query is used to initialize the form, so that the state of the form is
preserved from invocation to invocation.
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| CGI output
|
The results of executing a CGI script. The results
are either sent to standard output, or by
outputting the location of the result document
(either a full URL or a local virtual path).
The script sends its output to stdout: either a document generated by
the script, or instructions to the server for retrieving the desired
output. The back-end returns its results to the server as a data stream.
The server is responsible for "packaging" the data stream according to
HTTP, and for using HTTP to transport the data stream to the
requesting client. The server normally adds the needed HTTP headers to
the back-end's results.
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| Chat
|
Chat software provides the ability to "talk" using your keyboard in
real-time with other people on a network of computers like the Internet
or a company Intranet.
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| Checkbox
|
A field on a form which, when selected, enters
a check in the box. These form input tags are
best used to select members of small sets.
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| Chop
|
A Perl function that chops off the last character of a string and
returns the character chopped; primarily to remove the newline from
the end of an input record.
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| Client Headers
|
Data received from the browser by a CGI script.
The header lines are placed into the environment with the prefix
HTTP_ followed by the header name. Any - characters in the header name
are changed to _
characters. The server may exclude any headers which it has already
processed, such as
Authorization, Content-type, and Content-length. If necessary, the
server may choose
to exclude any or all of these headers if including them would exceed
any system environment limits.
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| Client-side imagemaps
|
A graphic with sub-areas that are linked to different URLs.
The MAP that relates parts of the
image to different URLs is stored in the current file.
This saves a round trip to the server, and should display
pages faster. Destination URLs can be
displayed in the browser status line as the mouse selects portions
of the imagemap.
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| Cookies
|
A general mechanism which server side connections (such as CGI
scripts) can use to both store and retrieve information on the
client side of the connection. The addition of a simple, persistent,
client-side state significantly extends the capabilities of
Web-based client/server applications.
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| Color
|
Colors can be specified in HTML using their names or
hexadecimal RGB codes.
There are 16 widely known color names:
| Aqua | #00FFFF |
Black | #000000 |
Blue | #0000FF |
| Fuchsia | #FF00FF |
Gray | #808080 |
Green | #008000 |
| Lime | #00FF00 |
Maroon | #800000 |
Navy | #000080 |
| Olive | #808000 |
Purple | #800080 |
Red | #FF0000 |
| Silver | #C0C0C0 |
Teal | #008080 |
Yellow | #FFFF00 |
and White, #FFFFFF.
These colors were originally picked as being the standard
16 colors supported with the Windows VGA palette.
The above gives the RGB values in hex (#RRGGBB).
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| CSS
|
Cascading Style Sheets A mechanism that allows authors and readers to attach the
same style (e.g. fonts, colors and spacing) to multiple HTML documents. The CSS
language is human readable and writable, and expresses style in common desktop publishing
terminology. One of the fundamental features of CSS is that style sheets cascade; authors
can attach a preferred style sheet, while the reader may have a personal style sheet to
adjust for human or technological handicaps.
|
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