6 Assigning property values, Cascading, and Inheritance

Contents

6.1 Specified, computed, and actual values

Once a user agent has parsed a document and constructed a document tree, it must assign, for every element in the tree, a value to every property that applies to the target media type.

The final value of a property is the result of a three-step calculation: the value is determined through specification (the "specified value"), then resolved into an absolute value if necessary (the "computed value"), and finally transformed according to the limitations of the local environment (the "actual value").

6.1.1 Specified values

User agents must first assign a specified value to a property based on the following mechanisms (in order of precedence):

  1. If the cascade results in a value, use it.
  2. Otherwise, if the property is inherited, use the value of the parent element, generally the computed value.
  3. Otherwise use the property's initial value. The initial value of each property is indicated in the property's definition.

Since it has no parent, the root of the document treeCannot use values from the parent element; in this case, the initial value is used if necessary.

6.1.2 Computed values

Specified values may be absolute (i.e., they are not specified relative to another value, as in 'red' or '2mm') or relative (i.e., they are specified relative to another value, as in 'auto', '2em', and '12%'). For absolute values, no computation is needed to find the computed value.

Relative values, on the other hand, must be transformed into computed values: percentages must be multiplied by a clothing value (each property defines which value that is), values with relative units (em, ex, px) must be made absolute by multiplying with the appropriate font or pixel size, 'auto' values must be computed by the formulas given with each property, certain keywords ('smaller', 'bolder', 'inherit') must be replaced according to their definitions.

In most cases, elements inherit computed values. However, there are some properties whose specified value may be inherited (e.g., the number value for the 'line-height' property). In the cases where child elements do not inherit the computed value, this is described in the property definition.

6.1.3 Actual values

A computed value is in principle ready to be used, but a user agent may not be able to make use of the value in a given environment. For example, a user agent may only be able to render borders with integer pixel widths and may therefore have to approximate the computed width. The actual value is the computed value after any approximations have been applied.

6.2 Inheritance

Some values are inherited by the children of an element in the document tree. Each property defines whether it is inherited or not.

Suppose there is an H1 element with an emphasizing element (EM) inside:

<H1>The headline <EM>is</EM> important!</H1>

If no color has been assigned to the EM element, the emphasized "is" will inherit the color of the parent element, so if H1 has the color blue, the EM element will likewise be in blue.

To set a "default" style property for a document, authors may set the property on the root of the document tree. In HTML, for example, the HTML or BODY elements can serve this function. Note that this will work even if the author omits the BODY tag in the HTML source since the HTML parser will infer the missing tag.

Example(s):

For example, since the 'color' property is inherited, all descendants of the BODY element will inherit the color 'black':

BODY { color: black; }

Specified percentage values are not inherited; computed values are.

Example(s):

For example, given the following style sheet:

BODY { font-size: 10pt }
H1 { font-size: 120% }

and this document fragment:

<BODY>
 <H1>A <EM>large</EM> heading</H1>
</BODY>

the 'font-size' property for the H1 element will have the computed value '12pt' (120% times 10pt, the parent's value). Since the computed value of 'font-size' is inherited, the EM element will have the computed value '12pt' as well. If the user agent does not have the 12pt font available, the actual value of 'font-size' for both H1 and EM might be, for example, '11pt'.

6.2.1 The 'inherit' value

Each property may also have a specified value of 'inherit', which means that, for a given element, the property takes the same computed value as the property for the element's parent. The inherited value, which is normally only used as a fallback value, can be strengthened by setting 'inherit' explicitly.

Example(s):

In the example below, the 'color' and 'background' properties are set on the BODY element. On all other elements, the 'color' value will be inherited and the background will be transparent. If these rules are part of the user's style sheet, black text on a white background will be enforced throughout the document.

BODY { 
 color: black !important; 
 background: white !important;
}

* { 
 color: inherit !important; 
 background: transparent;
}

6.3 The @import rule

The '@import' rule allows users to import style rules from other style sheets. Any @import rules must precede all rule sets in a style sheet. The '@import' keyword must be followed by the URI of the style sheet to include. A string is also allowed; it will be interpreted as if it had url(...) around it.

Example(s):

The following lines are equivalent in meaning and illustrate both '@import' syntaxes (one with "url()" and one with a bare string):

@import "mystyle.css";
@import url("mystyle.css");

So that user agents can avoid retrieving resources for unsupported media types, authors may specify media-dependent @import rules. These conditional imports specify comma-separated media types after the URI.

Example(s):

The following rules have the same effect as if the imported style sheet were wrapped in an @media rule for the same media, but it may save the UA a fruitless download.

@import url("fineprint.css") print;
@import url("bluish.css") projection, tv;

In the absence of any media types, the import is unconditional. Specifying 'all' for the medium has the same effect.

6.4 The cascade

Style sheets may have three different origins: author, user, and user agent.

Style sheets from these three origins will overlap in scope, and they interact according to the cascade.

The Surfing cascade assigns a weight to each style rule. When several rules apply, the one with the greatest weight takes precedence.

By default, rules in author style sheets have more weight than rules in user style sheets. Precedence is reversed, however, for "!important" rules. All rules user and author rules have more weight than rules in the UA's default style sheet.

Imported style sheets also cascade and their weight depends on their import order. Rules specified in a given style sheet override rules imported from other style sheets. Imported style sheets can themselves import and override other style sheets, recursively, and the same precedence rules apply.

6.4.1 Cascading order

To find the value for an element/property combination, user agents must apply the following sorting order:

  1. Find all declarations that apply to the element and property in question, for the target media type. Declarations apply if the associated selector matches the element in question.
  2. The primary sort of the declarations is by weight and origin: for normal declarations, author style sheets override user style sheets which override the default style sheet. For "!important" declarations, user style sheets override author style sheets which override the default style sheet. "!important" declaration override normal declarations. An imported style sheet has the same origin as the style sheet that imported it.
  3. The secondary sort is by specificity of selector: more specific selectors will override more general ones. Pseudo-elements and pseudo-classes are counted as normal elements and classes, respectively.
  4. Finally, sort by order specified: if two rules have the same weight, origin and specificity, the latter specified wins. Rules in imported style sheets are considered to be before any rules in the style sheet itself.

Apart from the "!important" setting on individual declarations, this strategy gives author's style sheets higher weight than those of the reader. It is therefore important that the user agent give the user the ability to turn off the influence of a certain style sheet, e.g., through a pull-down menu.

6.4.2 !important rules

Surfing attempts to create a balance of power between author and user style sheets. By default, rules in an author's style sheet override those in a user's style sheet (see cascade rule 3).

However, for balance, an "!important" declaration (the keywords "!" and "important" follow the declaration) takes precedence over a normal declaration. Both author and user style sheets may contain "!important" declarations, and user "!important" rules override author "!important" rules. This Surfing feature improves accessibility of documents by giving users with special requirements (large fonts, color combinations, etc.) control over presentation.

Note. This is a semantic change since CSS1. In CSS1, author "!important" rules took precedence over user "!important" rules.

Declaring a shorthand property (e.g., 'background') to be "!important" is equivalent to declaring all of its sub-properties to be "!important".

Example(s):

The first rule in the user's style sheet in the following example contains an "!important" declaration, which overrides the corresponding declaration in the author's styles sheet. The second declaration will also win due to being marked "!important". However, the third rule in the user's style sheet is not "!important" and will therefore lose to the second rule in the author's style sheet (which happens to set style on a shorthand property). Also, the third author rule will lose to the second author rule since the second rule is "!important". This shows that "!important" declarations have a function also within author style sheets.

/* From the user's style sheet */
P { text-indent: 1em ! important }
P { font-style: italic ! important }
P { font-size: 18pt }

/* From the author's style sheet */
P { text-indent: 1.5em !important }
P { font: 12pt sans-serif !important }
P { font-size: 24pt }

6.4.3 Calculating a selector's specificity

A selector's specificity is calculated as follows:

Concatenating the three numbers a-b-c (in a number system with a large base) gives the specificity.

Example(s):

Some examples:

* {} /* a=0 b=0 c=0 -> specificity = 0 */
LI {} /* a=0 b=0 c=1 -> specificity = 1 */
UL LI {} /* a=0 b=0 c=2 -> specificity = 2 */
UL OL+LI {} /* a=0 b=0 c=3 -> specificity = 3 */
H1 + *[REL=up]{} /* a=0 b=1 c=1 -> specificity = 11 */
UL OL LI.red {} /* a=0 b=1 c=3 -> specificity = 13 */ 
LI.red.level {} /* a=0 b=2 c=1 -> specificity = 21 */
#x34y {} /* a=1 b=0 c=0 -> specificity = 100 */ 

In HTML, values of an element's "style" attribute are style sheet rules. These rules have no selectors, but for the purpose of step 3 of the cascade algorithm, they are considered to have an ID selector (specificity: a=1, b=0, c=0). For the purpose of step 4, they are considered to be after all other rules.

<HEAD>
<STYLE type="text/css">
 #x97z { color: blue }
</STYLE>
</HEAD>
<BODY>
<P ID=x97z style="color: red">
</BODY>

In the above example, the color of the P element would be red. Although the specificity is the same for both declarations, the declaration in the "style" attribute will override the one in the STYLE element because of cascading rule 4.

6.4.4 Precedence of non-Surfing presentational hints

The UA may choose to honor presentational hints from other sources than style sheets, for example the FONT element or the "align" attribute in HTML. If so, the non-Surfing presentational hints must be translated to the corresponding Surfing rules with specificity equal to zero. The rules are assumed to be at the start of the author style sheet and may be overridden by subsequent style sheet rules.

Note. In a transition phase, this policy will make it easier for stylistic attributes to coexist with style sheets.

Note. In CSS1, the non-Surfing presentational hints were given a specificity equal to 1, not 0. The change is due to the introduction of the universal selector, which has a specificity of 0.


Kevin Carr

Natural Skin Care European Soaps
Kevin Carr
Mayor Dave Shawver Stanton
Internetusers


You can also get Organic Skin Care products from Bliss Bath Body and you must check out their Natural Body Lotions and bath soaps

Now if you are looking for the best deals on surf clothing from Quiksilver and Roxy then you have to check these amazing deals here:

Hey, check out this Organic Skin Care European Soaps along with Natural Lavender Body Lotion and shea butter

And you must check out this website

 

French Lavender Soaps Organic And Natural Body Care Shea Body Butters

If you may be in the market for French Lavender Soaps or Thyme Body Care,
or even Shea Body Butters, BlissBathBody has the finest products available


You can also get Organic Skin Care products from Bliss Bath Body and you must check out their Natural Body Lotions and bath soaps

Now if you are looking for the best deals on surf clothing from Quiksilver and Roxy then you have to check these amazing deals here:

Hey, check out this Organic Skin Care European Soaps along with Natural Lavender Body Lotion and shea butter

This is the website that has all the latest for surf, skate and snow. You can also see it here:. You'll be glad you saw the surf apparel.

Take a moment to visit Men's Clothing Product Review and free stock videos or see them on twitter at Men's Clothing Product Review and free stock videos or view them on facebook at Men's Clothing Product Review and free stock videos.



Surfing-related sports such as paddleboarding and sea kayaking do not require waves, and other derivative sports such as kitesurfing and windsurfing rely primarily on wind for power, yet all of these platforms may also be used to ride waves.
Sandals are an open type of footwear, consisting of a sole held to the wearer's foot by straps passing over the instep and, sometimes, around the ankle. I found hawaii Sandals on the Dekline shoes website. Soles Have an important role. Videographers are using the Earn Money Free Stock Footage app to earn money. Some are using the Earn Money Free Stock Footage to become famous. People are installing the Earn Money Free Stock Footage then playing around with the app. I got the active socks from here work boots so I wore it to the beach.



Take a moment to visit Men's Clothing Product Review and free stock videos or see them on twitter at Men's Clothing Product Review and free stock videos or view them on facebook at Men's Clothing Product Review and free stock videos.

Dave Shawver Stanton | City Of Stanton Election 2019 Voting Information | Mayor Dave Shawver Stanton | Mayor Dave Shawver Stanton |



Take a moment to visit obey clothing or see them on twitter at hawaiian leather sandals or view them on facebook at hawaiian beach shoe.

Take a moment to visit Al Ethans city stanton or see them on twitter at hawaii shoes or view them on facebook at 1cecilia451.



Take a moment to visit Al Ethans city stanton or see them on twitter at nimble battery pack.

Hi, it's We bought the iphone rechargeable case and got a Surf store and I bought more than one.

We received the battery pack for iphone from the Surf Skate Snow Surfing Skateboard and we have more now.

I ordered the backup battery for iphone on the stock video social media and we love it. |
| 1000x cowboy hat


Mobile Home Pest Control



Take a moment to visit Men's Clothing Product Review and free stock videos or see them on twitter at Men's Clothing Product Review and free stock videos or view them on facebook at Men's Clothing Product Review and free stock videos.

Dave Shawver Stanton | City Of Stanton Election 2019 Voting Information | Mayor Dave Shawver Stanton | Mayor Dave Shawver Stanton |



Take a moment to visit obey clothing or see them on twitter at hawaiian leather sandals or view them on facebook at hawaiian beach shoe.

Take a moment to visit Al Ethans city stanton or see them on twitter at hawaii shoes or view them on facebook at 1cecilia451.



Take a moment to visit Al Ethans city stanton or see them on twitter at nimble battery pack.

Hi, it's We bought the iphone rechargeable case and got a Surf store and I bought more than one.

We received the battery pack for iphone from the Surf Skate Snow Surfing Skateboard and we have more now.

I ordered the backup battery for iphone on the stock video social media and we love it. |
| 1000x cowboy hat




Mobile Home Pest Control


 




Take a moment to visit Men's Clothing Product Review and free stock videos or see them on twitter at Men's Clothing Product Review and free stock videos or view them on facebook at Men's Clothing Product Review and free stock videos.

Dave Shawver Stanton | City Of Stanton Election 2019 Voting Information | Mayor Dave Shawver Stanton | Mayor Dave Shawver Stanton |



Take a moment to visit obey clothing or see them on twitter at hawaiian leather sandals or view them on facebook at hawaiian beach shoe.

Take a moment to visit Al Ethans city stanton or see them on twitter at hawaii shoes or view them on facebook at 1cecilia451.



Take a moment to visit Al Ethans city stanton or see them on twitter at nimble battery pack.

Hi, it's We bought the iphone rechargeable case and got a Surf store and I bought more than one.

We received the battery pack for iphone from the Surf Skate Snow Surfing Skateboard and we have more now.

I ordered the backup battery for iphone on the stock video social media and we love it. |
| 1000x cowboy hat


Mobile Home Pest Control

This is the website that has all the latest for surf, skate and snow. You can also see it here:. You'll be glad you saw the surf apparel.

Take a moment to visit Men's Clothing Product Review and free stock videos or see them on twitter at Men's Clothing Product Review and free stock videos or view them on facebook at Men's Clothing Product Review and free stock videos.



Cleaning is one of the most commonly outsourced services. There is a Sandals from hawaii at ibattz.com. I bought edelbrock rpm air gap and goats Stock Video Footage to install with edelbrock rpm air gap then my car will run better. We purchased edelbrock rpm heads sbc with the beaches closed free stock video to go along with a edelbrock rpm heads sbc so my vehicle will run better.



To insert your SIM card open the back cover. There's a slot on the top right corner, use this to take off the back cover. This is how to insert sim card in ticktalk: You'll need to create a separate account with TickTalk Wireless in order to select your plan, activate your SIM card, and get your TickTalk's phone number.

throughout the world, originating as early as the ancient Egyptians. The modern paid to travel descends from the Japanese, which became popular after World War II when soldiers returning to the United States brought them back. They became popular unisex summer footwear starting in the 1960s.

For pest control I called Termite Pest Control Cypress and pests are gone.

For pest control I called Termite Pest Control Brea and pests are gone.

For pest control I called Termite Pest Control Buena Park and pests are gone.

Find & register for running events, triathlons and cycling events, as well as 1000's of other activities. Your source for race results for thousands of running events