HTML and CSS Reference
In-Depth Information
Table 15-1.
Generated Content Properties
Property
Initial Value
Description
content
normal
Defines the content to be inserted by the pseudo-element.
counter-increment
none
Increments the specified counter for a numbered sequence. To
increment in steps greater than
1
, also specify an integer.
A negative integer creates a back-counting sequence.
counter-reset
none
Resets the specified counter or creates it if it doesn't already exist.
By default, counters are initialized at
0
. To specify a different start
value, add an integer after the counter name.
quotes
Defines the styles of quotation marks at any number of nested
levels. The default value depends on the browser.
Defining the Content to be Inserted
The
content
property is extremely versatile. It accepts any of the following values:
none
The pseudo-element is not generated
.
normal
Same as
none
.
A string:
Literal text that is to be inserted.
url()
An external resource, usually an image
.
A counter:
A function that generates a numbered sequence.
attr(x)
Use the value of the
x
attribute in the selected element
.
open-quote
Insert an opening quote as defined by the
quotes
property
.
close-quote
Insert a closing quote as defined by the
quotes
property
.
no-open-quote
Omit the opening quote, but move to the next level of nesting
.
no-close-quote
Omit the closing quote, but move up to the previous level
.
Apart from the
none
and
normal
keywords, you can combine any of these values as a space-separated list to
create complex content that is injected before or after an element.
Inserting Images and Text
Using the
::before
and
::after
pseudo-elements to insert images, text, or a combination of the two can be
useful in situations where you need to label elements in a consistent way. For example, throughout this topic
points of interest are highlighted as Notes, Tips, or Cautions. The styles in image_text.html use the following three
classes to mark up paragraphs in a similar way (see Figure
15-1
):
.note::before {
content: url(images/square gray.gif) ' Note ';
font-weight: bold;