CSS Property

A CSS property is a parameter used in cascading style sheet to influence the CSS engine. The CSS specification defines a list of properties with a set of key information for rendering the source document.

CSS Property Definitions

In general, a CSS property can be summarized with a set of key information in form of CSS property definitions. That is

'property-name' <value>:legal values & syntaxcss1 Initial:initial valuecss1 Applies to:elements this property applies tocss1 Inherited:whether the propety is inheritedcss1 Percentages:how percentage values are interpretedcss1 Media:which media groups the property applies tocss1,2.1 Computed value:how to compute the computed valuecss1,2.1

'property-name'

'property-name' specifies the name of propery

<value>

<value> specifies the set of valid values for the property, 'property-name',

Initial

Initial specifies the initial value of the property , 'property-name',

Applies to

Applies to specifies the lists of the elements to which the propety , 'property-name', applies

Inherited

Inherited indicates whether the value of the property, 'property-name', is inherited from an ancestor element.

Percentages

Percentages indicates how percentages should be interpreted, if percentage value occur in the value of the property, 'property-name'.

Media

Media indicates the media groups to which the property, 'property-name', applies.

Computed value

Computed value describes the computed value for the property, 'property-name'.

Shorthand Property

Shorthand property is not a specific CSS parameter, but a shorthand for a set of CSS properties. Some properties are shorthand properties designed for specifying the values of several properties with a single property

Type of Property Values

Three types of property values are used in CSS specification, that is numeric unit value, keyword value, and data type value.

• numeric value: a specific numeric value. For examples, 100, etc.
• keyword value: a word with value of specific meaning in CSS specification, For examples, auto, disc, inherit, etc.
• data type value: a value, numeric unit or keyword value, selected from a set of specific values. For examples,
  • <integer>: a value selected from the set of integer values.
  • <numebr>: a value selected from the set of real number values.
  • <length>: a value of format with a numeric value immediately followed by a unit identifier.
  •  <percentage>: a value of format with a numeric value immediately followed by '%'.
  • <border-style>: a value from the set of pre-defined border-style values.
  • <'list-style-type'>: a value from the set of possible values of the 'list-style-type' property

Syntax of Property Value

Property Value Separator

The arrangement of component values of property values are:

Several juxtaposed wordsall values must occur in the given order. A bar (|) separatorseparates two or more alternative values however exactly only one alternative value must occur. A double bar (||) separatorseparates two or more option values and one or more options must occur but can be in any order. A double ampersand (&&) separatorseparates two or more value component values and all of component must occur but can be in any order. Bracket ([ ]) pair groups values, value options, or value components together as one component value.

Juxtaposition is stronger than the double ampersand, the double ampersand is stronger than the double bar, and the double bar is stronger than the bar. While bracketed values is considered as one component group.

Property Value Modifier

Every value, type, keyword, or bracketed group, may be followed by a modifier:

An asterisk (*)the preceding value occurs zero or more times. A plus (+)the preceding value occurs one or more times A question mark (?)the preceding value is optionl A pair of numbers in curly braces ({A,B})the preceding value occurs at least A and at most B times.