Master Series
Cascading
Style Sheets (CSS); Learning More
By William
Bontrager
In the "Cascading
Style Sheets (CSS) -- Getting Started"
article, the first in this series, you learned how to use an
external style sheet. You simply include one line of code on your
pages to affect the entire page with the style specified in that
external style sheet.
This article will show you how to embed a style sheet directly
into your web page. It will also show you how to define custom
styles, styles not associated with any particular HTML tags.
There are four ways a style can be applied to a web page:
1. Styles are specified through the use of an external
file, a method called "external style sheet" or
"linked style sheet." There is one file on your
site that specifies the styles. Then, one line in
each of your web pages links to that file. To change
the style on all your web pages, simply change the
external file. This is the method you learned in
the first article in this series.
2. Styles are specified in the HEAD area of each page
the style is applied to. This method is called
"embedded style sheet" and is the method you'll
learn in this article.
3. A style is specified in the actual HTML tag where
the style is applied. This is called an "inline
style." This will be addresses in a future article.
4. A combination of embedded and external style sheets.
For this, each page has an embedded style sheet.
Within the embedded style sheet are certain codes
that import one or more external style sheets. This
method is called "imported style sheet." This will
be addresses in a future article.
Using an Embedded
Style Sheet
To use an embedded style sheet, create a test page and insert
these seven lines into the HEAD area:
<STYLE TYPE="text/css">
<!--
BODY, TD, P, LI, BLOCKQUOTE {
font-family: sans-serif;
}
-->
</STYLE>
There is no need to
upload the test page to your server. It can be tested right from
your hard drive.
That's all there is to it. The text on your test page is
"magically" converted to a sans-serif font according to
the style you've defined.
Note: If you have FONT tags specified in the source code of your
test page, those will need to be removed so the CSS style can do
its job.
You can specify exact font names instead of the generic
sans-serif, serif, or monospace. If the font name is available on
the user's computer then it will be used. Arial and Helvetica are
common sans-serif fonts for PC and Mac desktop computers. To
control the exact font name to be used, with backups in case the
one you specify isn't available on the user's computer, list the
font names in order of preference, separated with a comma.
You've undoubtedly noticed that the method of defining a style is
exactly the same whether you're using the embedded style sheet
presented in this article or the external style sheet presented in
"Cascading Style Sheets (CSS) -- Getting Started"
If you used the CSS definitions presented in that previous article
and made them into an embedded style sheet, this would be the
result:
<STYLE TYPE="text/css">
<!--
BODY, TD, P, LI, BLOCKQUOTE {
font-family: arial,helvetica,sans-serif;
font-size: 14px;
color: #000000;
}
H1 {
font-size: 36px;
font-weight: bold;
text-align: center;
color: red;
background: blue;
}
A:link {
color: yellow;
background: red;
font-weight: bold;
}
A:active {
text-decoration: underline;
}
A:visited {
color: red;
background: yellow;
font-style: italic;
text-decoration: line-through;
}
A:hover {
text-decoration: none;
color: purple;
background: pink;
font-size: 22px;
font-weight: bold;
}
-->
</STYLE>
The method of
specifying styles is the same whether you embed the style sheet or
use an external file.
Using an external style sheet, all the style definitions are
contained in one file. Using an embedded style sheet, each page
has it's own definitions. With the former, you can change the
style of many web pages by changing only the one file containing
the style definitions. With the latter, you can change the style
of individual pages with no effect on others.
Defining and Using Custom Styles
Regardless of what type of style sheet you use, you can define
your own custom styles.
When you create a custom style, the name you give the style must
not match any HTML tags. When you define the style, the name must
begin with a period, but when you use the style then don't type
the period.
Here is an example of a basic style for common text tags and a
custom style:
<STYLE TYPE="text/css">
<!--
BODY, TD, P, LI, BLOCKQUOTE {
font-family: arial,helvetica,sans-serif;
font-size: 14px;
color: #000000;
}
.reallybad {
font-size: 24px;
font-weight: bold;
font-style: italic;
text-decoration: underline;
color: #CCCCCC;
background: #333333;
}
-->
</STYLE>
Custom
styles are used within HTML tags to change the style of the entire
tag -- DIV, SPAN, P, TD, etc. A custom style, once defined, is
called a "class." Thus, to use a certain style, you use
the "class" attribute and the class name as the value.
When you specify a style in an HTML tag, it overrides whatever
style, if any, that was previously defined for that tag. Here are
a couple examples:
<p class="reallybad">Hello everyone!</p>
<p>Hello <span class="reallybad">everyone!</span></p>
In the first example line, the entire paragraph is printed with
style "reallybad". In the second line, only the word
"everyone!" is printed with that style
("Hello" being printed with whatever style is defined
for the P tag).
You can define and use as many different custom styles as you
please.
Some of the styles demonstrated in the examples cause dramatic
effects. They serve to demonstrate possibilities. Your actual
implementation will probably be more pleasant to the eyes.
Will Bontrager
About the Author:
Copyright 2003 Bontrager Connection, LLC
William
Bontrager
Programmer/Publisher, "WillMaster Possibilities" ezine
mailto:[email protected]
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