Introduction to CSS
What is CSS?
- CSS stands for Cascading Style
Sheets
- Styles define how to display HTML
elements
- Styles are normally stored in Style Sheets
- Styles were added to HTML 4.0 to solve a
problem
- External Style Sheets can save you a lot of work
- External Style Sheets are stored in CSS
files
- Multiple style definitions will cascade
into one
Note: With CSS, your HTML
documents can be displayed using different output styles:
Styles Solve a Common Problem
HTML tags were originally designed
to define the content of a document. They were supposed to say "This is a
header", "This is a paragraph", "This is a table", by
using tags like <h1>, <p>, <table>, and so on. The layout of
the document was supposed to be taken care of by the browser, without using any
formatting tags.
As the two major browsers -
Netscape and Internet Explorer - continued to add new HTML tags and attributes
(like the <font> tag and the color attribute) to the original HTML
specification, it became more and more difficult to create Web sites where the
content of HTML documents was clearly separated from the document's
presentation layout.
To solve this problem, the World
Wide Web Consortium (W3C) - the non profit, standard setting consortium,
responsible for standardizing HTML - created STYLES in addition to HTML
4.0.
All major browsers support
Cascading Style Sheets.
Style Sheets Can Save a Lot
of Work
Styles sheets define HOW HTML
elements are to be displayed, just like the font tag and the color attribute in
HTML 3.2. Styles are normally saved in external .css
files. External style sheets enable you to change the appearance and layout of
all the pages in your Web, just by editing one single CSS document!
CSS is a breakthrough in Web
design because it allows developers to control the style and layout of multiple
Web pages all at once. As a Web developer you can define a style for each HTML
element and apply it to as many Web pages as you want. To make a global change,
simply change the style, and all elements in the Web are updated automatically.
Multiple Styles Will Cascade Into One
Style sheets allow style
information to be specified in many ways. Styles can be specified inside a
single HTML element, inside the <head> element of an HTML page, or in an
external CSS file. Even multiple external style sheets can be referenced inside
a single HTML document.
Cascading Order
What style will be used when
there is more than one style specified for an HTML element?
Generally speaking we can say that all the styles will "cascade" into
a new "virtual" style sheet by the following rules, where number four
has the highest priority:
1. Browser default
2. External style sheet
3. Internal style sheet
(inside the <head> tag)
4. Inline style (inside an
HTML element)
So, an inline style (inside an
HTML element) has the highest priority, which means that it will override a
style declared inside the <head> tag, in an external style sheet, or in a
browser (a default value).
Syntax
The CSS syntax is made up of three
parts: a selector, a property and a value:
selector {property: value} |
The selector is normally the HTML
element/tag you wish to define, the property is the attribute you wish to
change, and each property can take a value. The property and value are
separated by a colon, and surrounded by curly braces:
body {color: black} |
Note: If the
value is multiple words, put quotes around the value:
p {font-family: "sans serif"} |
Note: If you wish to specify more than one
property, you must separate each property with a semicolon. The example below
shows how to define a center aligned paragraph, with a red text color:
p {text-align:center;color:red} |
To make the style definitions more
readable, you can describe one property on each line, like this:
p{text-align: center;color: black;font-family: arial} |
Grouping
You can group selectors. Separate
each selector with a comma. In the example below we have grouped all the header
elements. All header elements will be displayed in green text color:
h1,h2,h3,h4,h5,h6 {color: green} |
The class Selector
With the class selector you can
define different styles for the same type of HTML element.
Say that you would like to have
two types of paragraphs in your document: one right-aligned paragraph, and one
center-aligned paragraph. Here is how you can do it with styles:
p.right {text-align: right} p.center {text-align: center} |
You have to use the class
attribute in your HTML document:
<p class="right">This paragraph will be right-aligned.</p><p class="center">This paragraph will be center-aligned.</p> |
Note: To apply more than one class per given
element, the syntax is:
<p class="center bold">This is a paragraph.</p> |
The paragraph above will be styled
by the class "center" AND the class "bold".
You can also omit the tag name in
the selector to define a style that will be used by all HTML elements that have
a certain class. In the example below, all HTML elements with
class="center" will be center-aligned:
.center {text-align: center} |
In the code below both the h1
element and the p element have class="center". This means that both
elements will follow the rules in the ".center" selector:
<h1 class="center">This heading will be center-aligned</h1><p class="center">This paragraph will also be center-aligned.</p> |
|
|
Do NOT
start a class name with a number! It will not work in Add Styles to Elements with Particular
Attributes
You can also apply styles to HTML
elements with particular attributes.
The style rule below will match
all input elements that have a type attribute with a value of "text":
input[type="text"] {background-color: blue} |
The id Selector
You can also define styles for
HTML elements with the id selector. The id selector is defined as a #.
The style rule below will match
the element that has an id attribute with a value of "green":
#green {color: green} |
The style rule below will match
the p element that has an id with a value of "para1":
p#para1{text-align: center;color: red} |
|
|
CSS Comments
Comments are used to explain your
code, and may help you when you edit the source code at a later date. A comment
will be ignored by browsers. A CSS comment begins with "/*", and ends
with "*/", like this:
/* This is a comment */p{text-align: center;/* This is another comment */color: black;font-family: arial} |
How to Insert a Style Sheet
When a browser reads a style
sheet, it will format the document according to it. There are three ways of
inserting a style sheet:
External Style Sheet
An external style sheet is ideal
when the style is applied to many pages. With an external style sheet, you can
change the look of an entire Web site by changing one file. Each page must link
to the style sheet using the <link> tag. The <link> tag goes inside
the head section:
<head><link rel="stylesheet" type="text/css"href="mystyle.css" /> </head> |
The browser will read the style
definitions from the file mystyle.css, and format the
document according to it.
An external style sheet can be
written in any text editor. The file should not contain any html tags. Your
style sheet should be saved with a .css extension. An
example of a style sheet file is shown below:
hr {color: sienna}p {margin-left: 20px}body {background-image: url("images/back40.gif")} |
|
|
Internal Style Sheet
An internal style sheet should be
used when a single document has a unique style. You define internal styles in
the head section by using the <style> tag, like this:
<head><style type="text/css">hr {color: sienna}p {margin-left: 20px}body {background-image: url("images/back40.gif")}</style></head> |
The browser will now read the
style definitions, and format the document according to it.
Note: A browser normally ignores unknown tags.
This means that an old browser that does not support styles,
will ignore the <style> tag, but the content of the <style> tag
will be displayed on the page. It is possible to prevent an old browser from
displaying the content by hiding it in the HTML comment element:
<head><style type="text/css"><!--hr {color: sienna}p {margin-left: 20px}body {background-image: url("images/back40.gif")}--></style></head> |
Inline Styles
An inline style loses many of the
advantages of style sheets by mixing content with presentation. Use this method
sparingly, such as when a style is to be applied to a single occurrence of an element.
To use inline styles you use the
style attribute in the relevant tag. The style attribute can contain any CSS
property. The example shows how to change the color and the left margin of a
paragraph:
<p style="color: sienna; margin-left: 20px">This is a paragraph</p> |
Multiple Style Sheets
If some properties have been set
for the same selector in different style sheets, the values will be inherited
from the more specific style sheet.
For example, an external style
sheet has these properties for the h3 selector:
h3 {color: red;text-align: left;font-size: 8pt} |
And an internal style sheet has
these properties for the h3 selector:
h3 {text-align: right; font-size: 20pt} |
If the page with the internal
style sheet also links to the external style sheet the properties for h3 will
be:
color: red; text-align: right; font-size: 20pt |
The color is inherited from the
external style sheet and the text-alignment and the font-size is replaced by
the internal style sheet.
CSS BACKGROUND
The CSS background properties
define the background effects of an element.
CSS Background Properties
The CSS background properties
allow you to control the background color of an element, set an image as the
background, repeat a background image vertically or horizontally, and position
an image on a page.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
A shorthand property for setting all background properties in
one declaration |
background-color |
4 |
1 |
6 |
1 |
|
|
Sets whether a background image is fixed or scrolls with the
rest of the page |
scroll |
4 |
1 |
6 |
1 |
|
|
Sets the background color of an element |
color-rgb |
4 |
1 |
4 |
1 |
|
|
Sets an image as the background |
url(URL) |
4 |
1 |
4 |
1 |
|
|
Sets the starting position of a background image |
top left |
4 |
1 |
6 |
1 |
|
|
Sets if/how a background image will be repeated |
repeat |
4 |
1 |
4 |
1 |
CSS TEXT
The CSS text properties define the
appearance of text.
CSS Text Properties
The CSS text properties allow you
to control the appearance of text. It is possible to change the color of a
text, increase or decrease the space between characters in a text, align a
text, decorate a text, indent the first line in a text, and more.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
Sets the color of a text |
color |
3 |
1 |
4 |
1 |
|
|
Sets the text direction |
ltr |
6 |
1 |
6 |
2 |
|
|
Sets the distance between lines |
normal |
4 |
1 |
4 |
1 |
|
|
Increase or decrease the space between characters |
normal |
4 |
1 |
6 |
1 |
|
|
Aligns the text in an element |
left |
4 |
1 |
4 |
1 |
|
|
Adds decoration to text |
none |
4 |
1 |
4 |
1 |
|
|
Indents the first line of text in an element |
length |
4 |
1 |
4 |
1 |
|
|
text-shadow |
|
none |
|
|
|
|
|
Controls the letters in an element |
none |
4 |
1 |
4 |
1 |
|
|
unicode-bidi |
|
normal |
5 |
|
|
2 |
|
Sets how white space inside an element is handled |
normal |
5 |
1 |
4 |
1 |
|
|
Increase or decrease the space between words |
normal |
6 |
1 |
6 |
1 |
CSS FONT
The CSS font properties define the
font in text.
CSS Font Properties
The CSS font properties allow you
to change the font family, boldness, size, and the style of a text.
Note: In CSS1 fonts are identified by a font
name. If a browser does not support the specified font, it will use a default
font.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
A shorthand property for setting all of the properties for a
font in one declaration |
font-style |
4 |
1 |
4 |
1 |
|
|
A prioritized list of font family names and/or generic family
names for an element |
family-name |
3 |
1 |
4 |
1 |
|
|
Sets the size of a font |
xx-small |
3 |
1 |
4 |
1 |
|
|
Specifies an aspect value for an element that will preserve the
x-height of the first-choice font |
none |
- |
- |
- |
2 |
|
|
Condenses or expands the current font-family |
normal |
- |
- |
- |
2 |
|
|
Sets the style of the font |
normal |
4 |
1 |
4 |
1 |
|
|
Displays text in a small-caps font or a normal font |
normal |
4 |
1 |
6 |
1 |
|
|
Sets the weight of a font |
normal |
4 |
1 |
4 |
1 |
CSS BORDER
The CSS border properties define
the borders around an element.
CSS Border Properties
The CSS border properties allow
you to specify the style and color of an element's border. In HTML we use
tables to create borders around a text, but with the CSS border properties we
can create borders with nice effects, and it can be applied to any element.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
A shorthand property for setting all of the properties for the
four borders in one declaration |
border-width |
4 |
1 |
4 |
1 |
|
|
A shorthand property for setting all of the properties for the
bottom border in one declaration |
border-bottom-width |
4 |
1 |
6 |
1 |
|
|
Sets the color of the bottom border |
border-color |
4 |
1 |
6 |
2 |
|
|
Sets the style of the bottom border |
border-style |
4 |
1 |
6 |
2 |
|
|
Sets the width of the bottom border |
thin |
4 |
1 |
4 |
1 |
|
|
Sets the color of the four borders, can have from one to four
colors |
color |
4 |
1 |
6 |
1 |
|
|
A shorthand property for setting all of the properties for the
left border in one declaration |
border-left-width |
4 |
1 |
6 |
1 |
|
|
Sets the color of the left border |
border-color |
4 |
1 |
6 |
2 |
|
|
Sets the style of the left border |
border-style |
4 |
1 |
6 |
2 |
|
|
Sets the width of the left border |
thin |
4 |
1 |
4 |
1 |
|
|
A shorthand property for setting all of the properties for the
right border in one declaration |
border-right-width |
4 |
1 |
6 |
1 |
|
|
Sets the color of the right border |
border-color |
4 |
1 |
6 |
2 |
|
|
Sets the style of the right border |
border-style |
4 |
1 |
6 |
2 |
|
|
Sets the width of the right border |
thin |
4 |
1 |
4 |
1 |
|
|
Sets the style of the four borders, can have from one to four
styles |
none |
4 |
1 |
6 |
1 |
|
|
A shorthand property for setting all of the properties for the
top border in one declaration |
border-top-width |
4 |
1 |
6 |
1 |
|
|
Sets the color of the top border |
border-color |
4 |
1 |
6 |
2 |
|
|
Sets the style of the top border |
border-style |
4 |
1 |
6 |
2 |
|
|
Sets the width of the top border |
thin |
4 |
1 |
4 |
1 |
|
|
A shorthand property for setting the width of the four borders
in one declaration, can have from one to four values |
thin |
4 |
1 |
4 |
1 |
CSS OUTLINE
The CSS outline properties is used
to draw a line around an element, outside the border edge.
CSS Outline Properties
An outline is a line that is drawn
around elements, outside the border edge, to make the element "stand
out".
The CSS outline properties sets
the outlines around elements. You can specify the style, color, and width of
the outline.
Note: Outlines do not take up space, and they do
not have to be rectangular.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
A shorthand property for setting all the outline properties in
one declaration |
outline-color |
- |
1.5 |
- |
2 |
|
|
Sets the color of the outline around an element |
color |
- |
1.5 |
- |
2 |
|
|
Sets the style of the outline around an element |
none |
- |
1.5 |
- |
2 |
|
|
Sets the width of the outline around an element |
thin |
- |
1.5 |
- |
2 |
CSS MARGIN
The CSS margin properties define
the space around elements.
CSS Margin Properties
The CSS margin properties define
the space around elements. It is possible to use negative values to overlap
content. The top, right, bottom, and left margin can be changed independently
using separate properties. A shorthand margin property can also be used to
change all of the margins at once.
Note: Netscape and IE give the body tag a
default margin of 8px. Opera does not! Instead, Opera applies a default padding
of 8px, so if one wants to adjust the margin for an entire page and have it
display correctly in Opera, the body padding must be set as well!
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
A shorthand property for setting the margin properties in one
declaration |
margin-top |
4 |
1 |
4 |
1 |
|
|
Sets the bottom margin of an element |
auto |
4 |
1 |
4 |
1 |
|
|
Sets the left margin of an element |
auto |
3 |
1 |
4 |
1 |
|
|
Sets the right margin of an element |
auto |
3 |
1 |
4 |
1 |
|
|
Sets the top margin of an element |
auto |
3 |
1 |
4 |
1 |
CSS PADDING
The CSS padding properties define
the space between the element border and the element content.
CSS Padding Properties
The CSS padding properties define
the space between the element border and the element content. Negative values
are not allowed. The top, right, bottom, and left padding can be changed
independently using separate properties. A shorthand padding property is also
created to control multiple sides at once.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
A shorthand property for setting all of the padding
properties in one declaration |
padding-top |
4 |
1 |
4 |
1 |
|
|
Sets the bottom padding of an element |
length |
4 |
1 |
4 |
1 |
|
|
Sets the left padding of an element |
length |
4 |
1 |
4 |
1 |
|
|
Sets the right padding of an element |
length |
4 |
1 |
4 |
1 |
|
|
Sets the top padding of an element |
length |
4 |
1 |
4 |
1 |
CSS LIST
The CSS list properties allow you
to place the list-item marker, change between different list-item markers, or
set an image as the list-item marker.
CSS List Properties
The CSS list properties allow you
to place the list-item marker, change between different list-item markers, or
set an image as the list-item marker.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
A shorthand property for setting all of the properties for a
list in one declaration |
list-style-type |
4 |
1 |
6 |
1 |
|
|
Sets an image as the list-item marker |
none |
4 |
1 |
6 |
1 |
|
|
Sets where the list-item marker is placed in the list |
inside |
4 |
1 |
6 |
1 |
|
|
Sets the type of the list-item marker |
none |
4 |
1 |
4 |
1 |
|
|
marker-offset |
|
auto |
|
1 |
7 |
2 |
CSS TABLE
The CSS table properties allow you
to set the layout of a table.
CSS Table Properties
The CSS table properties allow you
to set the layout of a table.
Browser support: IE: Internet Explorer, M: Mac IE only, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
Sets whether the table borders are collapsed into a single
border or detached as in standard HTML |
collapse |
5 |
1 |
7 |
2 |
|
|
Sets the distance that separates cell borders (only for the
"separated borders" model) |
length length |
5M |
1 |
6 |
2 |
|
|
Sets the position of the table caption |
top |
5M |
1 |
6 |
2 |
|
|
Sets whether or not to show empty cells in a table (only for the
"separated borders" model) |
show |
5M |
1 |
6 |
2 |
|
|
Sets the algorithm used to display the table cells, rows, and
columns |
auto |
5 |
1 |
6 |
2 |
CSS DIMENSION
The CSS dimension properties allow
you to control the height and width of an element. It also allows you to
increase the space between two lines.
CSS Dimension Properties
The CSS dimension properties allow
you to control the height and width of an element. It also allows you to
increase the space between two lines.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
Sets the height of an element |
auto |
4 |
1 |
6 |
1 |
|
|
Sets the distance between lines |
normal |
4 |
1 |
4 |
1 |
|
|
Sets the maximum height of an element |
none |
- |
1 |
6 |
2 |
|
|
Sets the maximum width of an element |
none |
- |
1 |
6 |
2 |
|
|
Sets the minimum height of an element |
length |
- |
1 |
6 |
2 |
|
|
Sets the minimum width of an element |
length |
- |
1 |
6 |
2 |
|
|
Sets the width of an element |
auto |
4 |
1 |
4 |
1 |
CSS CLASSIFICATION
The CSS classification properties
allow you to specify how and where to display an element.
CSS Classification Properties
The CSS classification properties
allow you to control how to display an element, set where an image will appear
in another element, position an element relative to its normal position,
position an element using an absolute value, and how to control the visibility
of an element.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
Sets the sides of an element where other floating elements are
not allowed |
left |
4 |
1 |
4 |
1 |
|
|
Specifies the type of cursor to be displayed |
url |
4 |
1 |
6 |
2 |
|
|
Sets how/if an element is displayed |
none |
4 |
1 |
4 |
1 |
|
|
Sets where an image or a text will appear in another element |
left |
4 |
1 |
4 |
1 |
|
|
Places an element in a static, relative, absolute or fixed
position |
static |
4 |
1 |
4 |
2 |
|
|
Sets if an element should be visible or invisible |
visible |
4 |
1 |
6 |
2 |
CSS Positioning
The CSS positioning properties
allows you to position an element.
CSS Positioning Properties
The CSS positioning properties
allow you to specify the left, right, top, and bottom position of an element.
It also allows you to set the shape of an element, place an element behind
another, and to specify what should happen when an element's content is too big
to fit in a specified area.
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Property |
Description |
Values |
IE |
F |
N |
W3C |
|
Sets how far the bottom edge of an element is above/below the
bottom edge of the parent element |
auto |
5 |
1 |
6 |
2 |
|
|
Sets the shape of an element. The element is clipped into this
shape, and displayed |
shape |
4 |
1 |
6 |
2 |
|
|
Sets how far the left edge of an element is to the right/left of
the left edge of the parent element |
auto |
4 |
1 |
4 |
2 |
|
|
Sets what happens if the content of an element overflow its area |
visible |
4 |
1 |
6 |
2 |
|
|
Places an element in a static, relative, absolute or fixed
position |
static |
4 |
1 |
4 |
2 |
|
|
Sets how far the right edge of an element is to the left/right
of the right edge of the parent element |
auto |
5 |
1 |
6 |
2 |
|
|
Sets how far the top edge of an element is above/below the top
edge of the parent element |
auto |
4 |
1 |
4 |
2 |
|
|
Sets the vertical alignment of an element |
baseline |
4 |
1 |
4 |
1 |
|
|
Sets the stack order of an element |
auto |
4 |
1 |
6 |
2 |
CSS Pseudo-classes
CSS pseudo-classes are used to add
special effects to some selectors.
Syntax
The syntax of pseudo-classes:
selector:pseudo-class {property: value} |
CSS classes can also be used with
pseudo-classes:
selector.class:pseudo-class {property: value} |
Anchor Pseudo-classes
A link that is active, visited,
unvisited, or when you mouse over a link can all be displayed in different ways
in a CSS-supporting browser:
a:link {color: #FF0000} /* unvisited link */ a:visited {color: #00FF00} /* visited link */ a:hover {color: #FF00FF} /* mouse over link */ a:active {color: #0000FF} /* selected link */ |
Note: a:hover
MUST come after a:link and a:visited
in the CSS definition in order to be effective!!
Note: a:active
MUST come after a:hover in the CSS definition in
order to be effective!!
Note: Pseudo-class names are not case-sensitive.
Pseudo-classes and CSS Classes
Pseudo-classes can be combined
with CSS classes:
a.red:visited {color: #FF0000} <a class="red" href="css_syntax.asp">CSS Syntax</a> |
If the link in the example above
has been visited, it will be displayed in red.
CSS2 - The :first-child
Pseudo-class
The :first-child pseudo-class matches a specified
element that is the first child of another element.
Note: For :first-child
to work in IE. A <!DOCTYPE> must be declared.
|
In this example, the selector
matches any p element that is the first child of a div element, and
indents the first paragraph inside a div element: div > p:first-child{text-indent:25px}
This selector will match the
first paragraph inside the div in the following HTML: <div><p>First paragraph in div.This paragraph will be indented.</p><p>Second paragraph in div.This paragraph will not be indented.</p></div>
but it will not match the
paragraph in this HTML: <div><h1>Header</h1><p>The first paragraph inside the div.This paragraph will not be indented.</p></div> |
|
In this example, the selector
matches any em element that is the first child
of a p element, and sets the font-weight to bold for the first em inside a p element: p:first-child em {font-weight:bold}
For example, the em in the HTML below is the first child of the paragraph: <p>I am a <em>strong</em> man.</p> |
|
In this example, the selector
matches any a element that is the first child of any element, and sets
the text-decoration to none: a:first-child {text-decoration:none}
For example, the first a in the
HTML below is the first child of the paragraph and will not be underlined.
But the second a in the paragraph is not the first child of the paragraph and
will be underlined: <p>Visit <a href="http://www.w3schools.com">W3Schools</a>and learn CSS! Visit <a href="http://www.w3schools.com">W3Schools</a>and learn HTML! </p> |
CSS2 - The :lang Pseudo-class
The :lang
pseudo-class allows you to define special rules for different languages. In the
example below, the :lang
class defines the type of quotation marks for q elements with a lang attribute with a value of "no":
<html><head><style type="text/css">q:lang(no) {quotes: "~" "~"}</style></head><body><p>Some text <q lang="no">A quote in a paragraph</q>Some text.</p></body></html> |
Pseudo-classes
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Pseudo-class |
Purpose |
IE |
F |
N |
W3C |
|
Adds special style to an activated element |
4 |
1 |
8 |
1 |
|
|
Adds special style to an element while the element has focus |
- |
1.5 |
8 |
2 |
|
|
Adds special style to an element when you mouse over it |
4 |
1 |
7 |
1 |
|
|
Adds special style to an unvisited link |
3 |
1 |
4 |
1 |
|
|
Adds special style to a visited link |
3 |
1 |
4 |
1 |
|
|
Adds special style to an element that is the first child of some
other element |
7 |
1 |
7 |
2 |
|
|
Allows the author to specify a language to use in a specified
element |
- |
1 |
8 |
2 |
CSS Pseudo-elements
CSS pseudo-elements are used to
add special effects to some selectors.
Syntax
The syntax of pseudo-elements:
selector:pseudo-element {property: value} |
CSS classes can also be used with
pseudo-elements:
selector.class:pseudo-element {property: value} |
The :first-line Pseudo-element
The "first-line" pseudo-element
is used to add special styles to the first line of the text in a selector:
p:first-line {color:#0000ff;font-variant:small-caps} <p>Some text that ends up on two or more lines</p> |
The output could be something like
this:
|
Some text that ends |
In the example above the browser
displays the first line formatted according to the "first-line"
pseudo element. Where the browser breaks the line depends on the size of
the browser window.
Note: The "first-line" pseudo-element
can only be used with block-level elements.
Note: The following properties apply to the
"first-line" pseudo-element:
- font properties
- color properties
- background properties
- word-spacing
- letter-spacing
- text-decoration
- vertical-align
- text-transform
- line-height
- clear
The :first-letter Pseudo-element
The "first-letter"
pseudo-element is used to add special style to the first letter of the text in
a selector:
p:first-letter {color:#ff0000;font-size:xx-large} <p>The first words of an article...</p> |
The output could be something like
this:
|
The first words of an article... |
Note: The "first-letter"
pseudo-element can only be used with block-level elements.
Note: The following properties apply to the
"first-letter" pseudo- element:
- font properties
- color properties
- background properties
- margin properties
- padding properties
- border properties
- text-decoration
- vertical-align (only if 'float' is 'none')
- text-transform
- line-height
- float
- clear
Pseudo-elements and CSS Classes
Pseudo-elements can be combined
with CSS classes:
p.article:first-letter {color:#ff0000} <p class="article">A paragraph in an article</p> |
The example above will make the
first letter of all paragraphs with class="article" red.
Multiple Pseudo-elements
Several pseudo-elements can be
combined:
p:first-letter {color:#ff0000;font-size:xx-large} p:first-line {color:#0000ff} <p>The first words of an article...</p> |
The output could be something like
this:
|
The first |
In the example above the first
letter of the paragraph will be red with a font size of 24pt. The rest of the
first line would be blue while the rest of the paragraph would be the default
color.
CSS2 - The :before
Pseudo-element
The ":before"
pseudo-element can be used to insert some content before an element.
The style below will play a sound
before each occurrence of an <h1> element:
|
h1:before |
CSS2 - The :after
Pseudo-element
The ":after"
pseudo-element can be used to insert some content after an element.
The style below will play a sound
after each occurrence of an <h1> element:
|
h1:after |
Pseudo-elements
Browser support: IE: Internet Explorer, F: Firefox, N: Netscape.
W3C: The number in the "W3C" column
indicates in which CSS recommendation the property is defined (CSS1 or CSS2).
|
Pseudo-element |
Purpose |
IE |
F |
N |
W3C |
|
Adds special style to the first letter of a text |
5 |
1 |
8 |
1 |
|
|
Adds special style to the first line of a text |
5 |
1 |
8 |
1 |
|
|
Inserts some content before an element |
|
1.5 |
8 |
2 |
|
|
Inserts some content after an element |
|
1.5 |
8 |
2 |
CSS Image Gallery
CSS can be used to create an image
gallery.
Image Gallery
The following image gallery is
created with CSS:
The source code looks like this:
<html><head><style type="text/css">div.img { margin: 2px; border: 1px solid #0000ff; height: auto; width: auto; float: left; text-align: center; }div.img img { display: inline; margin: 3px; border: 1px solid #ffffff; }div.img a:hover img { border: 1px solid #0000ff; }div.desc { text-align: center; font-weight: normal; width: 120px; margin: 2px; }</style></head><body><div class="img"> <a target="_blank" href="klematis_big.htm"> <img src="klematis_small.jpg" alt="Klematis" width="110" height="90" /> </a> <div class="desc">Add a description of the image here</div></div><div class="img"> <a target="_blank" href="klematis2_big.htm"> <img src="klematis2_small.jpg" alt="Klematis" width="110" height="90" /> </a> <div class="desc">Add a description of the image here</div></div><div class="img"> <a target="_blank" href="klematis3_big.htm"> <img src="klematis3_small.jpg" alt="Klematis" width="110" height="90" /> </a> <div class="desc">Add a description of the image here</div></div><div class="img"> <a target="_blank" href="klematis4_big.htm"> <img src="klematis4_small.jpg" alt="Klematis" width="110" height="90" /> </a> <div class="desc">Add a description of the image here</div></div></body></html> |
