Home  ›  Html and Css3 Second Edition Unit J Concepts Review

Html and Css3 Second Edition Unit J Concepts Review

Written By terça-feira, 19 de abril de 2022 Add Comment Edit

Style sheet language

Cascading Manner Sheets (CSS)
CSS3 logo and wordmark.svg
Filename extension

.css
Internet media type

text/css
Uniform Type Identifier (UTI) public.css
Developed by World Broad Web Consortium (W3C)
Initial release 17 December 1996; 25 years ago  (1996-12-17)
Latest release

CSS 2.1 : Level ii Revision 1
12 April 2016; half-dozen years ago  (2016-04-12)

Type of format Style sail language
Container for Style rules for HTML elements (tags)
Independent past HTML Documents
Open format? Yes
Website world wide web.w3.org/TR/CSS/#css

Cascading Style Sheets (CSS) is a manner sheet linguistic communication used for describing the presentation of a document written in a markup language such as HTML.[1] CSS is a cornerstone technology of the World wide web, alongside HTML and JavaScript.[2]

CSS is designed to enable the separation of presentation and content, including layout, colors, and fonts.[3] This separation can improve content accessibility; provide more than flexibility and command in the specification of presentation characteristics; enable multiple web pages to share formatting by specifying the relevant CSS in a divide .css file, which reduces complexity and repetition in the structural content; and enable the .css file to be buried to better the folio load speed between the pages that share the file and its formatting.

Separation of formatting and content as well makes it feasible to present the aforementioned markup page in different styles for unlike rendering methods, such as on-screen, in print, by voice (via speech-based browser or screen reader), and on Braille-based tactile devices. CSS likewise has rules for alternate formatting if the content is accessed on a mobile device.[4]

The name cascading comes from the specified priority scheme to determine which style rule applies if more one rule matches a particular element. This cascading priority scheme is predictable.

The CSS specifications are maintained by the World wide web Consortium (W3C). Internet media type (MIME blazon) text/css is registered for use with CSS by RFC 2318 (March 1998). The W3C operates a free CSS validation service for CSS documents.[5]

In addition to HTML, other markup languages support the utilize of CSS including XHTML, patently XML, SVG, and XUL.

Syntax [edit]

CSS has a simple syntax and uses a number of English language keywords to specify the names of various manner properties.

A manner sheet consists of a list of rules. Each rule or rule-set consists of one or more selectors, and a declaration block.

Selector [edit]

In CSS, selectors declare which role of the markup a way applies to by matching tags and attributes in the markup itself.

Selectors may apply to the post-obit:

  • all elements of a specific blazon, e.g. the second-level headers h2
  • elements specified by attribute, in particular:
    • id: an identifier unique within the document, identified with a hash prefix e.g. #id
    • grade: an identifier that can annotate multiple elements in a document, identified with a period prefix e.g. .classname
  • elements depending on how they are placed relative to others in the document tree.

Classes and IDs are case-sensitive, start with letters, and tin include alphanumeric characters, hyphens, and underscores. A class may apply to whatever number of instances of whatever elements. An ID may only be applied to a single chemical element.

Pseudo-classes are used in CSS selectors to permit formatting based on information that is non contained in the document tree. Ane example of a widely used pseudo-form is : hover , which identifies content only when the user "points to" the visible element, usually by belongings the mouse cursor over it. It is appended to a selector as in a : hover or # elementid : hover . A pseudo-course classifies document elements, such as : link or : visited , whereas a pseudo-element makes a pick that may consist of fractional elements, such as :: first-line or :: first-letter .[half dozen]

Selectors may exist combined in many means to achieve great specificity and flexibility.[vii] Multiple selectors may be joined in a spaced list to specify elements past location, element type, id, class, or any combination thereof. The society of the selectors is of import. For case, div . myClass { color : red ;} applies to all elements of course myClass that are within div elements, whereas . myClass div { color : red ;} applies to all div elements that are within elements of class myClass. This is non to be confused with concatenated identifiers such as div . myClass { colour : ruby-red ;} which applies to div elements of form myClass.

The following tabular array provides a summary of selector syntax indicating usage and the version of CSS that introduced it.[viii]

Pattern Matches First defined
in CSS level
E an element of type Eastward ane
Eastward : link an E element is the source anchor of a hyperlink of which the target is not withal visited (:link) or already visited (:visited) 1
East : active an E chemical element during certain user actions one
Due east :: first-line the first formatted line of an E element one
E :: start-letter the first formatted letter of an E chemical element i
. c all elements with form="c" 1
# myid the chemical element with id="myid" 1
Eastward . warning an E element whose form is "warning" (the document linguistic communication specifies how class is determined) 1
Eastward # myid an E element with ID equal to "myid" 1
. c # myid the chemical element with grade="c" and ID equal to "myid" ane
E F an F chemical element descendant of an E element 1
* whatever element 2
Due east [ foo ] an E element with a "foo" attribute 2
E [ foo = "bar" ] an Eastward chemical element whose "foo" attribute value is exactly equal to "bar" 2
E [ foo ~= "bar" ] an E chemical element whose "foo" attribute value is a listing of whitespace-separated values, one of which is exactly equal to "bar" 2
Eastward [ foo |= "en" ] an E element whose "foo" aspect has a hyphen-separated list of values commencement (from the left) with "en" 2
E : first-child an E element, first kid of its parent ii
E : lang ( fr ) an element of type E in linguistic communication "fr" (the certificate language specifies how language is determined) 2
East :: earlier generated content before an E chemical element's content 2
Due east :: afterwards generated content after an E chemical element's content two
East > F an F element child of an E element two
E + F an F element immediately preceded by an E element 2
East [ foo ^= "bar" ] an East element whose "foo" aspect value begins exactly with the string "bar" 3
E [ foo $= "bar" ] an E chemical element whose "foo" attribute value ends exactly with the string "bar" 3
E [ foo *= "bar" ] an East element whose "foo" attribute value contains the substring "bar" 3
E : root an E chemical element, root of the certificate iii
E : nth-kid ( northward ) an Due east element, the due north-thursday child of its parent 3
Due east : nth-last-child ( northward ) an E element, the n-thursday kid of its parent, counting from the last one iii
E : nth-of-blazon ( n ) an E element, the n-th sibling of its blazon 3
East : nth-last-of-type ( n ) an Due east element, the n-th sibling of its type, counting from the last ane 3
E : last-kid an E element, final child of its parent 3
Eastward : first-of-type an E chemical element, beginning sibling of its type iii
E : last-of-type an Due east chemical element, last sibling of its type iii
E : only-child an Due east chemical element, merely child of its parent iii
East : only-of-type an E element, only sibling of its type three
Due east : empty an Eastward chemical element that has no children (including text nodes) 3
East : target an E element existence the target of the referring URI 3
E : enabled a user interface element E that is enabled 3
E : disabled a user interface chemical element E that is disabled 3
E : checked a user interface element Eastward that is checked (for example a radio-button or checkbox) 3
E : not ( s ) an E chemical element that does not friction match elementary selector s three
Due east ~ F an F element preceded past an Eastward element 3

Declaration block [edit]

A declaration block consists of a list of declarations in braces. Each annunciation itself consists of a property, a colon (:), and a value. If in that location are multiple declarations in a block, a semi-colon (;) must be inserted to separate each announcement. An optional semi-colon after the last (or single) proclamation may exist used.[9]

Properties are specified in the CSS standard. Each holding has a set of possible values. Some properties can bear upon whatsoever type of element, and others apply only to particular groups of elements.[10] [11]

Values may be keywords, such as "center" or "inherit", or numerical values, such as 200px (200 pixels), 50vw (fifty percent of the viewport width) or 80% (80 percentage of the parent element's width). Color values can be specified with keywords (eastward.grand. "crimson"), hexadecimal values (e.g. #FF0000, also abbreviated as #F00), RGB values on a 0 to 255 calibration (e.g. rgb(255, 0, 0) ), RGBA values that specify both color and blastoff transparency (e.grand. rgba(255, 0, 0, 0.8)), or HSL or HSLA values (e.g. hsl(000, 100%, fifty%), hsla(000, 100%, 50%, 80%)).[12]

Length units [edit]

Non-zero numeric values representing linear measures must include a length unit, which is either an alphabetic lawmaking or abbreviation, as in 200px or 50vw; or a percentage sign, every bit in 80%. Some units – cm (centimetre); in (inch); mm (millimetre); pc (pica); and pt (signal) – are absolute, which means that the rendered dimension does non depend upon the structure of the folio; others – em (em); ex (ex) and px (pixel)[ clarification needed ] – are relative, which means that factors such every bit the font size of a parent chemical element can touch the rendered measurement. These 8 units were a feature of CSS 1[13] and retained in all subsequent revisions. The proposed CSS Values and Units Module Level 3 volition, if adopted equally a W3C Recommendation, provide seven further length units: ch; Q; rem; vh; vmax; vmin; and vw.[14]

Use [edit]

Before CSS, nigh all presentational attributes of HTML documents were contained within the HTML markup. All font colors, background styles, chemical element alignments, borders and sizes had to be explicitly described, often repeatedly, within the HTML. CSS lets authors move much of that information to some other file, the style canvass, resulting in considerably simpler HTML.

For example, headings (h1 elements), sub-headings (h2), sub-sub-headings (h3), etc., are defined structurally using HTML. In impress and on the screen, choice of font, size, color and emphasis for these elements is presentational.

Before CSS, certificate authors who wanted to assign such typographic characteristics to, say, all h2 headings had to repeat HTML presentational markup for each occurrence of that heading type. This made documents more than complex, larger, and more than error-prone and hard to maintain. CSS allows the separation of presentation from construction. CSS tin ascertain colour, font, text alignment, size, borders, spacing, layout and many other typographic characteristics, and can exercise so independently for on-screen and printed views. CSS as well defines non-visual styles, such as reading speed and emphasis for aural text readers. The W3C has at present deprecated the use of all presentational HTML markup.[15]

For case, nether pre-CSS HTML, a heading element defined with scarlet text would be written equally: 

                        <            h1            ><            font            color            =            "cherry"            >Chapter 1.</            font            ></            h1            >

Using CSS, the same element can exist coded using style properties instead of HTML presentational attributes: 

                        <            h1            style            =            "color: cherry-red;"            >Chapter ane.</            h1            >

The advantages of this may not exist immediately clear only the power of CSS becomes more apparent when the style properties are placed in an internal manner element or, fifty-fifty improve, an external CSS file. For example, suppose the certificate contains the mode element: 

                        <            style            >            h1            {            color            :            blood-red            ;            }            </            manner            >

All h1 elements in the document will and then automatically get ruby-red without requiring whatsoever explicit code. If the writer later wanted to make h1 elements blueish instead, this could be done by changing the style element to: 

                        <            style            >            h1            {            color            :            blue            ;            }            </            mode            >

rather than by laboriously going through the document and irresolute the colour for each private h1 element.

The styles can also be placed in an external CSS file, as described beneath, and loaded using syntax like to: 

                        <            link            href            =            "path/to/file.css"            rel            =            "stylesheet"            type            =            "text/css"            >

This further decouples the styling from the HTML document and makes it possible to restyle multiple documents past simply editing a shared external CSS file.

Sources [edit]

CSS data can be provided from various sources. These sources can exist the web browser, the user, and the author. The information from the author can be farther classified into inline, media type, importance, selector specificity, rule order, inheritance, and property definition. CSS way information can be in a separate document, or it can be embedded into an HTML document. Multiple manner sheets can be imported. Different styles can be applied depending on the output device being used; for example, the screen version can be quite different from the printed version, so that authors can tailor the presentation appropriately for each medium.

The style canvass with the highest priority controls the content brandish. Declarations not set in the highest priority source are passed on to a source of lower priority, such as the user agent style. The process is chosen cascading.

I of the goals of CSS is to allow users greater control over presentation. Someone who finds red italic headings difficult to read may utilize a different way sheet. Depending on the browser and the spider web site, a user may choose from various way sheets provided by the designers, or may remove all added styles and view the site using the browser's default styling, or may override just the red italic heading manner without altering other attributes.

CSS priority scheme (highest to lowest)
Priority CSS source type Description
i Importance The " ! important " note overwrites the previous priority types
2 Inline A manner applied to an HTML element via HTML "way" attribute
3 Media Blazon A property definition applies to all media types, unless a media specific CSS is divers
four User defined Most browsers have the accessibility characteristic: a user divers CSS
5 Selector specificity A specific contextual selector ( # heading p ) overwrites generic definition
6 Rule order Last dominion declaration has a college priority
vii Parent inheritance If a property is not specified, it is inherited from a parent element
8 CSS holding definition in HTML document CSS rule or CSS inline style overwrites a default browser value
9 Browser default The lowest priority: browser default value is determined by W3C initial value specifications

Specificity [edit]

Specificity refers to the relative weights of various rules.[16] It determines which styles employ to an chemical element when more than 1 dominion could apply. Based on specification, a simple selector (due east.thousand. H1) has a specificity of 1, class selectors have a specificity of 1,0, and ID selectors a specificity of 1,0,0. Considering the specificity values do non acquit over as in the decimal arrangement, commas are used to separate the "digits"[17] (a CSS rule having 11 elements and 11 classes would accept a specificity of 11,11, not 121).

Thus the following rules selectors result in the indicated specificity:

Selectors Specificity
h1 { colour : white ;} 0, 0, 0, 1
p em { colour : green ;} 0, 0, 0, 2
. grape { color : red ;} 0, 0, 1, 0
p . vivid { color : blue ;} 0, 0, one, 1
p . bright em . dark { colour : yellow ;} 0, 0, 2, 2
# id218 { color : brown ;} 0, 1, 0, 0
way = " " 1, 0, 0, 0

Examples [edit]

Consider this HTML fragment: 

                        <!DOCTYPE html>            <            html            >            <            head            >            <            meta            charset            =            "utf-eight"            >            <            manner            >            #            xyz            {            color            :            blue            ;            }            </            way            >            </            head            >            <            torso            >            <            p            id            =            "xyz"            style            =            "color: green;"            >To demonstrate specificity</            p            >            </            body            >            </            html            >

In the above example, the proclamation in the fashion attribute overrides the one in the <style> element because it has a college specificity, and thus, the paragraph appears light-green:

To demonstrate specificity

Inheritance [edit]

Inheritance is a key characteristic in CSS; it relies on the ancestor-descendant relationship to operate. Inheritance is the mechanism by which properties are applied not merely to a specified element, but too to its descendants.[16] Inheritance relies on the document tree, which is the hierarchy of XHTML elements in a folio based on nesting. Descendant elements may inherit CSS holding values from whatsoever ancestor element enclosing them. In general, descendant elements inherit text-related properties, merely their box-related properties are not inherited. Backdrop that tin be inherited are colour, font, alphabetic character-spacing, line-height, list-style, text-marshal, text-indent, text-transform, visibility, white-infinite and word-spacing. Properties that cannot be inherited are background, border, display, bladder and articulate, top, and width, margin, min- and max-elevation and -width, outline, overflow, padding, position, text-decoration, vertical-marshal and z-index.

Inheritance tin can exist used to avoid declaring certain properties over and over once more in a style canvas, assuasive for shorter CSS.

Inheritance in CSS is not the aforementioned every bit inheritance in class-based programming languages, where it is possible to define grade B equally "like class A, simply with modifications".[eighteen] With CSS, information technology is possible to style an chemical element with "grade A, but with modifications". Notwithstanding, it is not possible to define a CSS class B similar that, which could and then be used to style multiple elements without having to repeat the modifications.

Example [edit]

Given the following manner sheet:

Suppose there is an h1 chemical element with an emphasizing chemical element (<em>) inside: 

                        <            h1            >            This is to            <            em            >illustrate</            em            >            inheritance            </            h1            >

If no color is assigned to the em element, the emphasized give-and-take "illustrate" inherits the color of the parent element, h1. The style sheet h1 has the color pinkish, hence, the em element is likewise pinkish:

This is to illustrate inheritance

Whitespace [edit]

Whitespace between properties and selectors is ignored. This code snippet: 

                        trunk            {            overflow            :            subconscious            ;            background            :            #000000            ;            background-image            :            url            (            images/bg.gif            );            groundwork-repeat            :            no-repeat            ;            background-position            :            left            top            ;}

is functionally equivalent to this one: 

                        trunk            {            overflow            :            hidden            ;            background-color            :            #000000            ;            background-image            :            url            (            images/bg.gif            );            background-repeat            :            no-echo            ;            background-position            :            left            pinnacle            ;            }

One mutual style to format CSS for readability is to indent each property and give it its own line. In addition to formatting CSS for readability, autograph properties can be used to write out the code faster, which as well gets processed more quickly when being rendered:[19] 

                        body            {            overflow            :            hidden            ;            background            :            #000            url            (            images/bg.gif            )            no-repeat            left            top            ;            }

Sometimes, multiple property values are indented onto their own line:

                        @            font-face up            {            font-family            :            'Comic Sans'            font-size            :            20px            src            :            url            (            'first.example.com'            ),            url            (            'second.example.com'            ),            url            (            '3rd.example.com'            ),            url            (            'fourth.example.com'            ),            }

Positioning [edit]

CSS 2.1 defines iii positioning schemes:

Normal flow
Inline items are laid out in the same style every bit the letters in words in text, one after the other across the bachelor space until there is no more room, and so starting a new line below. Block items stack vertically, like paragraphs and like the items in a bulleted list. Normal flow also includes relative positioning of block or inline items, and run-in boxes.
Floats
A floated detail is taken out of the normal catamenia and shifted to the left or right as far as possible in the space bachelor. Other content then flows alongside the floated detail.
Accented positioning
An admittedly positioned item has no identify in, and no upshot on, the normal flow of other items. It occupies its assigned position in its container independently of other items.[20]

Position property [edit]

There are five possible values of the position belongings. If an detail is positioned in any way other than static , and then the further backdrop top , bottom , left , and right are used to specify offsets and positions.The element having position static is not affected by the top , bottom , left or right properties.

Static
The default value places the particular in the normal flow
Relative
The item is placed in the normal catamenia, then shifted or offset from that position. Subsequent menstruum items are laid out as if the detail had not been moved.
Absolute
Specifies accented positioning. The element is positioned in relation to its nearest non-static ancestor.
Stock-still
The item is absolutely positioned in a fixed position on the screen even as the rest of the document is scrolled[20]

Float and clear [edit]

The bladder property may have one of iii values. Admittedly positioned or fixed items cannot be floated. Other elements normally flow around floated items, unless they are prevented from doing and then by their clear holding.

left
The item floats to the left of the line that it would accept appeared in; other items may flow around its correct side.
right
The detail floats to the right of the line that it would have appeared in; other items may flow around its left side.
articulate
Forces the chemical element to announced underneath ('clear') floated elements to the left ( articulate : left ), right ( articulate : right ) or both sides ( clear : both ).[20] [21]

History [edit]

Håkon Wium Lie, chief technical officeholder of the Opera Software company and co-creator of the CSS web standards

CSS was kickoff proposed past Håkon Wium Lie on 10 October 1994.[22] At the time, Lie was working with Tim Berners-Lee at CERN.[23] Several other way canvas languages for the web were proposed effectually the same fourth dimension, and discussions on public mailing lists and inside World wide web Consortium resulted in the showtime W3C CSS Recommendation (CSS1)[24] beingness released in 1996. In particular, a proposal by Bert Bos was influential; he became co-author of CSS1, and is regarded equally co-creator of CSS.[25]

Fashion sheets take existed in one course or another since the beginnings of Standard Generalized Markup Language (SGML) in the 1980s, and CSS was adult to provide style sheets for the web.[26] I requirement for a spider web manner sheet language was for style sheets to come from dissimilar sources on the web. Therefore, existing mode sheet languages like DSSSL and FOSI were non suitable. CSS, on the other hand, let a certificate's fashion be influenced past multiple style sheets by way of "cascading" styles.[26]

As HTML grew, it came to encompass a wider multifariousness of stylistic capabilities to meet the demands of web developers. This evolution gave the designer more control over site appearance, at the cost of more complex HTML. Variations in web browser implementations, such as ViolaWWW and WorldWideWeb,[27] fabricated consequent site appearance hard, and users had less control over how web content was displayed. The browser/editor developed by Tim Berners-Lee had style sheets that were hard-coded into the programme. The style sheets could therefore non be linked to documents on the web.[23] Robert Cailliau, likewise of CERN, wanted to separate the structure from the presentation so that different fashion sheets could describe dissimilar presentation for printing, screen-based presentations, and editors.[27]

Improving web presentation capabilities was a topic of interest to many in the spider web community and 9 unlike fashion sail languages were proposed on the www-fashion mailing list.[26] Of these nine proposals, two were especially influential on what became CSS: Cascading HTML Way Sheets[22] and Stream-based Style Sheet Proposal (SSP).[25] [28] Two browsers served as testbeds for the initial proposals; Prevarication worked with Yves Lafon to implement CSS in Dave Raggett's Loonshit browser.[29] [thirty] [31] Bert Bos implemented his own SSP proposal in the Argo browser.[25] Thereafter, Lie and Bos worked together to develop the CSS standard (the 'H' was removed from the proper noun because these way sheets could as well be practical to other markup languages also HTML).[23]

Prevarication's proposal was presented at the "Mosaic and the Web" conference (later chosen WWW2) in Chicago, Illinois in 1994, and over again with Bert Bos in 1995.[23] Around this fourth dimension the W3C was already being established, and took an involvement in the evolution of CSS. Information technology organized a workshop toward that end chaired by Steven Pemberton. This resulted in W3C adding work on CSS to the deliverables of the HTML editorial review board (ERB). Lie and Bos were the principal technical staff on this aspect of the projection, with additional members, including Thomas Reardon of Microsoft, participating as well. In Baronial 1996, Netscape Advice Corporation presented an alternative way sail language chosen JavaScript Style Sheets (JSSS).[23] The spec was never finished, and is deprecated.[32] By the finish of 1996, CSS was prepare to become official, and the CSS level i Recommendation was published in December.

Evolution of HTML, CSS, and the DOM had all been taking identify in one group, the HTML Editorial Review Board (ERB). Early in 1997, the ERB was separate into three working groups: HTML Working grouping, chaired past Dan Connolly of W3C; DOM Working group, chaired by Lauren Wood of SoftQuad; and CSS Working group, chaired by Chris Lilley of W3C.

The CSS Working Group began tackling issues that had non been addressed with CSS level 1, resulting in the creation of CSS level two on November four, 1997. It was published as a W3C Recommendation on May 12, 1998. CSS level 3, which was started in 1998, is yet nether development every bit of 2014.

In 2005, the CSS Working Groups decided to enforce the requirements for standards more strictly. This meant that already published standards like CSS ii.ane, CSS 3 Selectors, and CSS 3 Text were pulled back from Candidate Recommendation to Working Draft level.

Difficulty with adoption [edit]

The CSS ane specification was completed in 1996. Microsoft's Internet Explorer 3[23] was released in that yr, featuring some express support for CSS. IE four and Netscape 4.x added more back up, but it was typically incomplete and had many bugs that prevented CSS from being usefully adopted. It was more than 3 years before whatsoever web browser achieved near-full implementation of the specification. Cyberspace Explorer 5.0 for the Macintosh, shipped in March 2000, was the commencement browser to have total (meliorate than 99 pct) CSS i support,[33] surpassing Opera, which had been the leader since its introduction of CSS back up fifteen months earlier. Other browsers followed soon later, and many of them additionally implemented parts of CSS 2.[ citation needed ]

Still, even when later 'version 5' web browsers began to offer a fairly full implementation of CSS, they were nevertheless wrong in certain areas and were fraught with inconsistencies, bugs and other quirks. Microsoft Internet Explorer 5.x for Windows, every bit opposed to the very unlike IE for Macintosh, had a flawed implementation of the 'CSS box model', as compared with the CSS standards. Such inconsistencies and variation in characteristic back up made it hard for designers to accomplish a consistent appearance beyond browsers and platforms without the use of workarounds termed CSS hacks and filters. The IE/Windows box model bugs were then serious that, when Internet Explorer 6 was released, Microsoft introduced a backwards-compatible mode of CSS estimation ('quirks mode') alongside an alternative, corrected 'standards mode'. Other non-Microsoft browsers also provided such 'manner'-switch behavior capability. It therefore became necessary for authors of HTML files to ensure they contained special distinctive 'standards-compliant CSS intended' mark to show that the authors intended CSS to exist interpreted correctly, in compliance with standards, as opposed to being intended for the now long-obsolete IE5/Windows browser. Without this marker, spider web browsers that have the 'quirks mode'-switching capability will size objects in web pages every bit IE5/Windows would rather than post-obit CSS standards.[ citation needed ]

Problems with patchy adoption of CSS, along with errata in the original specification, led the W3C to revise the CSS 2 standard into CSS 2.1, which moved nearer to a working snapshot of current CSS back up in HTML browsers. Some CSS 2 properties that no browser successfully implemented were dropped, and in a few cases, defined behaviors were changed to bring the standard into line with the predominant existing implementations. CSS 2.ane became a Candidate Recommendation on February 25, 2004, but CSS 2.1 was pulled back to Working Draft status on June 13, 2005,[34] and only returned to Candidate Recommendation status on July 19, 2007.[35]

In add-on to these problems, the .css extension was used past a software product used to catechumen PowerPoint files into Meaty Slide Evidence files,[36] so some web servers served all .css [37] equally MIME type application/10-pointplus [38] rather than text/css.

Vendor prefixes [edit]

Individual browser vendors occasionally introduced new parameters ahead of standardization and universalization. To forbid interfering with future implementations, vendors prepended unique names to the parameters, such as -moz- for Mozilla Firefox, -webkit- named after the browsing engine of Apple Safari, -o- for Opera Browser and -ms- for Microsoft Net Explorer.

Occasionally, the parameters with vendor prefix such as -moz-radial-gradient and -webkit-linear-gradient have slightly different syntax as compared to their non-vendor-prefix counterparts.[39]

Prefixed backdrop are rendered obsolete by the time of standardization. Programs are available to automatically add prefixes for older browsers, and to indicate out standardized versions of prefixed parameters. Since prefixes are limited to a small subset of browsers, removing the prefix allows other browsers to see the functionality. An exception is certain obsolete -webkit- prefixed properties, which are so mutual and persistent on the spider web that other families of browsers have decided to support them for compatibility.[40]

Variations [edit]

CSS has diverse levels and profiles. Each level of CSS builds upon the last, typically adding new features and typically denoted as CSS 1, CSS 2, CSS iii, and CSS 4. Profiles are typically a subset of 1 or more than levels of CSS built for a particular device or user interface. Currently there are profiles for mobile devices, printers, and television sets. Profiles should non be confused with media types, which were added in CSS 2.

CSS 1 [edit]

The first CSS specification to become an official W3C Recommendation is CSS level 1, published on 17 December 1996. Håkon Wium Prevarication and Bert Bos are credited as the original developers.[41] [42] Among its capabilities are support for

  • Font properties such as typeface and emphasis
  • Colour of text, backgrounds, and other elements
  • Text attributes such as spacing between words, messages, and lines of text
  • Alignment of text, images, tables and other elements
  • Margin, border, padding, and positioning for well-nigh elements
  • Unique identification and generic classification of groups of attributes

The W3C no longer maintains the CSS ane Recommendation.[43]

CSS two [edit]

CSS level 2 specification was adult by the W3C and published as a recommendation in May 1998. A superset of CSS 1, CSS 2 includes a number of new capabilities similar accented, relative, and stock-still positioning of elements and z-alphabetize, the concept of media types, back up for audible style sheets (which were later replaced by the CSS iii spoken language modules)[44] and bidirectional text, and new font properties such equally shadows.

The W3C no longer maintains the CSS ii recommendation.[45]

CSS two.1 [edit]

CSS level 2 revision ane, often referred to equally "CSS 2.1", fixes errors in CSS ii, removes poorly supported or not fully interoperable features and adds already implemented browser extensions to the specification. To comply with the W3C Process for standardizing technical specifications, CSS two.i went back and forth between Working Typhoon status and Candidate Recommendation status for many years. CSS ii.i first became a Candidate Recommendation on 25 February 2004, but it was reverted to a Working Typhoon on thirteen June 2005 for further review. It returned to Candidate Recommendation on 19 July 2007 and then updated twice in 2009. Nonetheless, because changes and clarifications were made, it again went back to Last Call Working Draft on seven December 2010.

CSS 2.i went to Proposed Recommendation on 12 April 2011.[46] After beingness reviewed by the W3C Advisory Committee, information technology was finally published as a W3C Recommendation on 7 June 2011.[47]

CSS 2.1 was planned as the first and terminal revision of level 2—but low priority piece of work on CSS 2.two began in 2015.

CSS three [edit]

Unlike CSS 2, which is a big single specification defining diverse features, CSS three is divided into several separate documents called "modules". Each module adds new capabilities or extends features divers in CSS 2, preserving backward compatibility. Work on CSS level three started around the time of publication of the original CSS 2 recommendation. The primeval CSS three drafts were published in June 1999.[48]

Due to the modularization, unlike modules take different stability and statuses.[49]

Some modules accept Candidate Recommendation (CR) condition and are considered moderately stable. At CR stage, implementations are brash to drop vendor prefixes.[fifty]

Summary of main module-specifications[51]
Module Specification title Status Appointment
css3-groundwork CSS Backgrounds and Borders Module Level three Candidate Rec. Dec 2020
css3-box CSS CSS Box Model Module Level 3 Candidate Rec. Dec 2020
css-pour-three CSS Cascading and Inheritance Level 3 Recommendation Feb 2021
css3-colour CSS Color Module Level 3 Recommendation Jun 2018
css3-content CSS Generated Content Module Level 3 Working Draft 2 Aug 2019
css-fonts-3 CSS Fonts Module Level 3 Recommendation Sep 2018
css3-gcpm CSS Generated Content for Paged Media Module Working Typhoon May 2014
css3-layout CSS Template Layout Module Note Mar 2015
css3-mediaqueries Media Queries Recommendation Jun 2012
mediaqueries-four Media Queries Level iv Candidate Rec. Jul 2020
css3-multicol Multi-cavalcade Layout Module Level 1 Working Typhoon February 2021
css3-page CSS Paged Media Module Level 3 Working Typhoon, and part migrated to css3-suspension Oct 2018
css3-break CSS Fragmentation Module Level iii Candidate Rec. December 2018
selectors-iii Selectors Level iii Recommendation November 2018
selectors-iv Selectors Level 4 Working Draft November 2018
css3-ui CSS Basic User Interface Module Level 3 (CSS3 UI) Recommendation Jun 2018

CSS 4 [edit]

Jen Simmons discussing the state of CSS in 2019, every bit several CSS4 modules were beingness advanced

There is no unmarried, integrated CSS4 specification,[52] considering the specification has been separate into many divide modules which level independently.

Modules that build on things from CSS Level 2 started at Level iii. Some of them have already reached Level 4 or are already budgeted Level v. Other modules that define entirely new functionality, such as Flexbox,[53] take been designated as Level 1 and some of them are approaching Level ii.

The CSS Working Group sometimes publishes "Snapshots", a collection of whole modules and parts of other drafts that are considered stable plenty to be implemented by browser developers. And so far, five such "best current practices" documents take been published as Notes, in 2007,[54] 2010,[55] 2015,[56] 2017,[57] and 2018.[58]

Since these specification snapshots are primarily intended for developers, at that place has been growing demand for every bit like versioned reference document targeted at authors, which would present the land of interoperable implementations as meanwhile documented by sites similar Can I Utilise…[59] and the MDN Spider web Docs.[60] A W3C Customs Grouping has been established in early 2020 in society to hash out and ascertain such a resource.[61] The actual kind of versioning is also upwards to fence, which means that the document once produced might non be called "CSS4".

Browser support [edit]

Each web browser uses a layout engine to render web pages, and support for CSS functionality is not consistent between them. Because browsers do not parse CSS perfectly, multiple coding techniques have been adult to target specific browsers with workarounds (commonly known as CSS hacks or CSS filters). Adoption of new functionality in CSS can be hindered by lack of back up in major browsers. For example, Internet Explorer was slow to add support for many CSS 3 features, which slowed adoption of those features and damaged the browser's reputation amidst developers.[62] In order to ensure a consistent experience for their users, web developers frequently test their sites across multiple operating systems, browsers, and browser versions, increasing development time and complexity. Tools such as BrowserStack have been built to reduce the complication of maintaining these environments.

In add-on to these testing tools, many sites maintain lists of browser support for specific CSS properties, including CanIUse and the MDN Web Docs. Additionally, the CSS three defines feature queries, which provide an @supports directive that volition allow developers to target browsers with support for sure functionality directly inside their CSS.[63] CSS that is not supported by older browsers can also sometimes exist patched in using JavaScript polyfills, which are pieces of JavaScript code designed to make browsers behave consistently. These workarounds—and the need to support fallback functionality—can add complexity to development projects, and consequently, companies frequently define a listing of browser versions that they will and volition not back up.

As websites adopt newer lawmaking standards that are incompatible with older browsers, these browsers can be cut off from accessing many of the resources on the web (sometimes intentionally).[64] Many of the most popular sites on the net are not just visually degraded on older browsers due to poor CSS support, but practise not work at all, in large function due to the evolution of JavaScript and other spider web technologies.

Limitations [edit]

Some noted limitations of the current capabilities of CSS include:

Selectors are unable to ascend
CSS currently offers no fashion to select a parent or ancestor of an element that satisfies certain criteria.[65] CSS Selectors Level 4, which is still in Working Draft condition, proposes such a selector,[66] but but as function of the complete "snapshot" selector profile, not the fast "alive" profile used in dynamic CSS styling.[67] A more advanced selector scheme (such equally XPath) would enable more sophisticated style sheets. The major reasons for the CSS Working Group previously rejecting proposals for parent selectors are related to browser performance and incremental rendering issues.[68]
Cannot explicitly declare new scope independently of position
Scoping rules for backdrop such equally z-index wait for the closest parent chemical element with a position:absolute or position:relative aspect. This odd coupling has undesired furnishings. For example, information technology is impossible to avoid declaring a new telescopic when one is forced to suit an chemical element's position, preventing one from using the desired scope of a parent element.
Pseudo-grade dynamic behavior not controllable
CSS implements pseudo-classes that allow a caste of user feedback by provisional application of alternate styles. One CSS pseudo-form, " : hover ", is dynamic (equivalent of JavaScript "onmouseover") and has potential for misuse (e.g., implementing cursor-proximity popups),[69] but CSS has no ability for a client to disable it (no "disable"-similar property) or limit its effects (no "nochange"-like values for each property).
Cannot proper noun rules
At that place is no mode to name a CSS dominion, which would allow (for example) client-side scripts to refer to the dominion even if its selector changes.
Cannot include styles from a rule into another dominion
CSS styles frequently must be duplicated in several rules to achieve a desired effect, causing additional maintenance and requiring more thorough testing. Some new CSS features were proposed to solve this, but were abandoned later on.[lxx] [71] Instead, authors may gain this ability by using more sophisticated stylesheet languages which compile to CSS, such as Sass, Less, or Stylus.
Cannot target specific text without altering markup
Besides the : first-alphabetic character pseudo-element, 1 cannot target specific ranges of text without needing to employ place-holder elements.

Former issues [edit]

Additionally, several more issues were present in prior versions of the CSS standard, but have been alleviated:

Vertical control limitations
Though horizontal placement of elements was e'er generally piece of cake to control, vertical placement was frequently unintuitive, convoluted, or outright impossible. Simple tasks, such every bit centering an element vertically or placing a footer no higher than bottom of the viewport required either complicated and unintuitive way rules, or simple simply widely unsupported rules.[65] The Flexible Box Module improved the situation considerably and vertical control is much more straightforward and supported in all of the modern browsers.[72] Older browsers still have those issues, but nearly of those (mainly Cyberspace Explorer 9 and below) are no longer supported by their vendors.[73]
Absence of expressions
At that place was no standard ability to specify property values as simple expressions (such as margin-left : 10 % – 3em + 4px ; ). This would be useful in a variety of cases, such equally calculating the size of columns subject to a constraint on the sum of all columns. Cyberspace Explorer versions 5 to 7 back up a proprietary expression() statement,[74] with like functionality. This proprietary expression() argument is no longer supported from Cyberspace Explorer viii onwards, except in compatibility modes. This decision was taken for "standards compliance, browser operation, and security reasons".[74] However, a candidate recommendation with a calc() value to address this limitation has been published by the CSS WG[75] and has since been supported in all of the modern browsers.[76]
Lack of column annunciation
Although possible in electric current CSS 3 (using the column-count module),[77] layouts with multiple columns can be complex to implement in CSS ii.1. With CSS 2.1, the procedure is often done using floating elements, which are often rendered differently by different browsers, dissimilar computer screen shapes, and different screen ratios set on standard monitors. All of the mod browsers support this CSS three feature in one form or another.[78]

Advantages [edit]

Separation of content from presentation
CSS facilitates publication of content in multiple presentation formats based on nominal parameters. Nominal parameters include explicit user preferences, different web browsers, the type of device existence used to view the content (a desktop computer or mobile device), the geographic location of the user and many other variables.
Site-broad consistency
When CSS is used effectively, in terms of inheritance and "cascading", a global mode canvas can be used to touch and fashion elements site-broad. If the situation arises that the styling of the elements should be changed or adjusted, these changes tin can exist made by editing rules in the global style sail. Before CSS, this sort of maintenance was more than hard, expensive and fourth dimension-consuming.
Bandwidth
A stylesheet, internal or external, specifies the way in one case for a range of HTML elements selected past grade, type or human relationship to others. This is much more efficient than repeating fashion data inline for each occurrence of the element. An external stylesheet is usually stored in the browser cache, and can therefore be used on multiple pages without being reloaded, further reducing information transfer over a network.
Page reformatting
With a simple change of one line, a different style sheet tin be used for the same page. This has advantages for accessibility, also as providing the power to tailor a page or site to different target devices. Furthermore, devices not able to empathise the styling nevertheless display the content.
Accessibility
Without CSS, spider web designers must typically lay out their pages with techniques such as HTML tables that hinder accessibility for vision-impaired users (see Tableless web pattern#Accessibility).

Standardization [edit]

Frameworks [edit]

CSS frameworks are pre-prepared libraries that are meant to allow for easier, more standards-compliant styling of web pages using the Cascading Style Sheets language. CSS frameworks include Blueprint, Bootstrap, Foundation and Materialize. Like programming and scripting linguistic communication libraries, CSS frameworks are usually incorporated as external .css sheets referenced in the HTML < caput > . They provide a number of ready-made options for designing and laying out the web folio. Although many of these frameworks have been published, some authors utilise them generally for rapid prototyping, or for learning from, and prefer to 'handcraft' CSS that is appropriate to each published site without the pattern, maintenance and download overhead of having many unused features in the site's styling.[79]

Design methodologies [edit]

Equally the size of CSS resources used in a projection increases, a development team often needs to decide on a mutual design methodology to keep them organized. The goals are ease of development, ease of collaboration during development and performance of the deployed stylesheets in the browser. Popular methodologies include OOCSS (object oriented CSS), ACSS (atomic CSS), oCSS (organic Cascade Manner Canvass), SMACSS (scalable and modular architecture for CSS), and BEM (block, element, modifier).[80]

See as well [edit]

  • Wink of unstyled content

References [edit]

  1. ^ "CSS programmer guide". MDN Spider web Docs. Archived from the original on 2015-09-25. Retrieved 2015-09-24 .
  2. ^ Flanagan, David (18 April 2011). JavaScript: the definitive guide. Beijing; Farnham: O'Reilly. p. 1. ISBN978-1-4493-9385-4. OCLC 686709345. JavaScript is role of the triad of technologies that all Web developers must learn: HTML to specify the content of spider web pages, CSS to specify the presentation of spider web pages, and JavaScript to specify the behavior of web pages.
  3. ^ "What is CSS?". Www Consortium. Archived from the original on 2010-eleven-29. Retrieved 2010-12-01 .
  4. ^ "Web-based Mobile Apps of the Future Using HTML v, CSS and JavaScript". HTMLGoodies. 23 July 2010. Archived from the original on 2014-10-20. Retrieved 2014-10-16 .
  5. ^ "W3C CSS validation service". Archived from the original on 2011-02-14. Retrieved 2012-06-thirty .
  6. ^ "W3C CSS2.ane specification for pseudo-elements and pseudo-classes". World wide web Consortium. 7 June 2011. Archived from the original on thirty April 2012. Retrieved 30 Apr 2012.
  7. ^ see the complete definition of selectors at the W3C Web site Archived 2006-04-23 at the Wayback Machine.
  8. ^ "Selectors Level 3". W3.org. Archived from the original on 2014-06-03. Retrieved 2014-05-thirty .
  9. ^ "W3C CSS2.1 specification for rule sets, proclamation blocks, and selectors". World wide web Consortium. seven June 2011. Archived from the original on 28 March 2008. Retrieved 2009-06-20 .
  10. ^ "Total property table". W3.org. Archived from the original on 2014-05-30. Retrieved 2014-05-30 .
  11. ^ "Index of CSS properties". www.w3.org . Retrieved 2020-08-09 .
  12. ^ "CSS Color". MDN Spider web Docs. 2016-06-28. Archived from the original on 2016-09-21. Retrieved 2016-08-23 .
  13. ^ "6.1 Length units". Cascading Style Sheets, level ane. 17 December 1996. Archived from the original on 14 June 2019. Retrieved 20 June 2019.
  14. ^ "5. Distance Units: the <length> type". CSS Values and Units Module Level 3. six June 2019. Archived from the original on vii June 2019. Retrieved twenty June 2019.
  15. ^ W3C HTML Working Group. "HTML 5. A vocabulary and associated APIs for HTML and XHTML". Www Consortium. Archived from the original on 15 July 2014. Retrieved 28 June 2014.
  16. ^ a b Meyer, Eric A. (2006). Cascading Manner Sheets: The Definitive Guide (3rd ed.). O'Reilly Media, Inc. ISBN0-596-52733-0. Archived from the original on 2014-02-fifteen. Retrieved 2014-02-16 .
  17. ^ "Assigning property values, Cascading, and Inheritance". Archived from the original on 2014-06-11. Retrieved 2014-06-10 .
  18. ^ "Can a CSS form inherit one or more other classes?". StackOverflow. Archived from the original on 2017-10-xiv. Retrieved 2017-09-10 .
  19. ^ "Shorthand backdrop". Tutorial. Mozilla Developers. 2017-12-07. Archived from the original on 2018-01-xxx. Retrieved 2018-01-30 .
  20. ^ a b c Bos, Bert; et al. (7 December 2010). "9.3 Positioning schemes". Cascading Mode Sheets Level 2 Revision ane (CSS two.one) Specification. W3C. Archived from the original on xviii February 2011. Retrieved 16 February 2011.
  21. ^ Holzschlag, Molly E (2005). Leap into HTML and CSS. Pearson Instruction, Inc. ISBN0-13-185586-7.
  22. ^ a b Lie, Hakon West (ten October 1994). "Cascading HTML style sheets – a proposal" (Proposal) (92). CERN. Archived from the original on iv June 2014. Retrieved 25 May 2014.
  23. ^ a b c d e f Lie, Håkon Wium; Bos, Bert (1999). Cascading Style Sheets, designing for the Web. Addison Wesley. ISBN0-201-59625-3 . Retrieved 23 June 2010.
  24. ^ "Cascading Fashion Sheets, level one". World Broad Web Consortium. Archived from the original on 2014-04-09. Retrieved 2014-03-07 .
  25. ^ a b c Bos, Bert (xiv April 1995). "Simple style sheets for SGML & HTML on the web". World Wide Web Consortium. Archived from the original on 23 September 2009. Retrieved twenty June 2010.
  26. ^ a b c "Cascading Style Sheets". University of Oslo. Archived from the original on 2006-09-06. Retrieved iii September 2014.
  27. ^ a b Petrie, Charles; Cailliau, Robert (November 1997). "Interview Robert Cailliau on the WWW Proposal: "How It Really Happened."". Constitute of Electrical and Electronics Engineers. Archived from the original on 6 January 2011. Retrieved 18 August 2010.
  28. ^ Bos, Bert (31 March 1995). "Stream-based Style canvas Proposal". Archived from the original on 12 October 2014. Retrieved iii September 2014.
  29. ^ Nielsen, Henrik Frystyk (7 June 2002). "Libwww Hackers". Www Consortium. Archived from the original on 2 December 2009. Retrieved half dozen June 2010.
  30. ^ "Yves Lafon". Www Consortium. Archived from the original on 24 June 2010. Retrieved 17 June 2010.
  31. ^ "The W3C Team: Technology and Society". Earth Broad Web Consortium. eighteen July 2008. Archived from the original on 28 May 2010. Retrieved 22 January 2011.
  32. ^ Lou Montulli; Brendan Eich; Scott Furman; Donna Converse; Troy Chevalier (22 August 1996). "JavaScript-Based Style Sheets". W3C. Archived from the original on 27 May 2010. Retrieved 23 June 2010.
  33. ^ "CSS software". W3.org. Archived from the original on 2010-11-25. Retrieved 2011-01-15 .
  34. ^ Anne van Kesteren. "CSS 2.1 – Anne's Weblog". Archived from the original on 2005-12-10. Retrieved 2011-02-16 .
  35. ^ "Archive of W3C News in 2007". Www Consortium. Archived from the original on 2011-06-28. Retrieved 2011-02-16 .
  36. ^ Nitot, Tristan (18 March 2002). "Wrong MIME Type for CSS Files". Mozilla Developer Center. Mozilla. Archived from the original on 2011-05-20. Retrieved 20 June 2010.
  37. ^ McBride, Don (27 November 2009). "File Types". Archived from the original on 29 October 2010. Retrieved xx June 2010.
  38. ^ "css file extension details". File extension database. 12 March 2010. Archived from the original on 18 July 2011. Retrieved 20 June 2010.
  39. ^ "How and why you would want to apply CSS vendor prefixes in your website". Lifewire. 2019-11-12.
  40. ^ "Compatibility Standard". WHATWG.
  41. ^ Bos, / Håkon Wium Prevarication, Bert (1997). Cascading style sheets: designing for the Web (1st print. ed.). Harlow, England; Reading, MA.: Addison Wesley Longman. ISBN0-201-41998-X.
  42. ^ W3C: Cascading Manner Sheets, level 1 Archived 2011-02-09 at the Wayback Machine CSS 1 specification
  43. ^ W3C: Cascading Style Sheets level 1 specification Archived 2011-02-11 at the Wayback Machine CSS level 1 specification
  44. ^ "Aural way sheets". W3C. Archived from the original on 2014-ten-26. Retrieved 2014-x-26 .
  45. ^ W3C: Cascading Style Sheets, level ii Archived 2011-01-16 at the Wayback Machine CSS ii specification (1998 recommendation)
  46. ^ W3C:Cascading Fashion Sheets, level two revision 1 Archived 2011-xi-09 at the Wayback Machine CSS 2.one specification (W3C Proposed Recommendation)
  47. ^ W3C: Cascading Manner Sheets Standard Boasts Unprecedented Interoperability Archived 2011-06-ten at the Wayback Machine
  48. ^ Bos, Bert (xviii Feb 2011). "Descriptions of all CSS specifications". Www Consortium. Archived from the original on 31 March 2011. Retrieved 3 March 2011.
  49. ^ Bos, Bert (26 February 2011). "CSS current work". World wide web Consortium. Archived from the original on 3 March 2011. Retrieved iii March 2011.
  50. ^ Etemad, Elika J. (12 December 2010). "Cascading Style Sheets (CSS) Snapshot 2010". World wide web Consortium. Archived from the original on 16 March 2011. Retrieved three March 2011.
  51. ^ "All CSS specifications". W3.org. 2014-05-22. Archived from the original on 2014-05-thirty. Retrieved 2014-05-thirty .
  52. ^ Atkins Jr, Tab. "A Word About CSS4". Archived from the original on 31 October 2012. Retrieved 18 Oct 2012.
  53. ^ "CSS Flexible Box Layout Module Level one". W3C. 19 November 2018. Archived from the original on nineteen October 2012. Retrieved 18 October 2012.
  54. ^ "Cascading Style Sheets (CSS) Snapshot 2007". 12 May 2011. Archived from the original on 8 August 2016. Retrieved eighteen July 2016.
  55. ^ "Cascading Fashion Sheets (CSS) Snapshot 2010". 12 May 2011. Archived from the original on sixteen March 2011. Retrieved 3 March 2011.
  56. ^ "CSS Snapshot 2015". W3C. thirteen October 2015. Archived from the original on 27 Jan 2017. Retrieved thirteen February 2017.
  57. ^ "CSS Snapshot 2017". 31 January 2017. Archived from the original on 13 February 2017. Retrieved 13 February 2017.
  58. ^ "CSS Snapshot 2018". 15 Nov 2018. Archived from the original on 1 February 2019. Retrieved two January 2019.
  59. ^ "Can I Use… Back up tables for HTML5, CSS3 etc". Archived from the original on 2018-02-xix. Retrieved 2019-01-26 .
  60. ^ "MDN Web Docs: CSS".
  61. ^ "CSS4 Community Group". Archived from the original on 2020-02-27. Retrieved 2020-02-27 .
  62. ^ "CSS3 Solutions for Internet Explorer – Smashing Magazine". Bang-up Mag. 2010-04-28. Archived from the original on 2016-ten-12. Retrieved 2016-ten-12 .
  63. ^ "Using Feature Queries in CSS ★ Mozilla Hacks – the Web developer blog". hacks.mozilla.org. Archived from the original on 2016-10-11. Retrieved 2016-10-12 .
  64. ^ "Looking at the Spider web with Internet Explorer 6, one last time". Ars Technica. Archived from the original on 2016-x-12. Retrieved 2016-10-12 .
  65. ^ a b Molly Holzschlag (January 2012). "Vii Things However Missing from CSS". .net Mag. Archived from the original on 2017-03-05. Retrieved 2017-03-04 .
  66. ^ "Selectors Level iv – Determining the Discipline of a Selector". W3.org. Archived from the original on 2013-08-17. Retrieved 2013-08-13 .
  67. ^ "Selectors Level 4 – Fast vs Consummate Selector Profiles". W3.org. Archived from the original on 2013-08-17. Retrieved 2013-08-thirteen .
  68. ^ Snook, Jonathan (October 2010). "Why nosotros don't take a parent selector". snook.ca. Archived from the original on 2012-01-18. Retrieved 2012-01-26 .
  69. ^ "Pure CSS Popups". meyerweb.com. Archived from the original on 2009-12-09. Retrieved 2009-11-19 .
  70. ^ Tab Atkins Jr. "CSS utilize rule". GitHub. Archived from the original on 2016-02-22. Retrieved 2016-02-27 .
  71. ^ "Why I Abased @apply — Tab Completion".
  72. ^ "CSS Flexible Box Layout Module". Can I utilise... Support tables for HTML5, CSS3, etc. CanIUse.com. Archived from the original on 2016-02-23.
  73. ^ "Internet Explorer End of Back up". Microsoft. Archived from the original on 2019-06-02. Retrieved 2016-02-27 .
  74. ^ a b "About Dynamic Properties". Msdn.microsoft.com. Archived from the original on 2017-10-fourteen. Retrieved 2009-06-20 .
  75. ^ "CSS Values and Units Module Level 3". W3.org. half-dozen June 2019. Archived from the original on 23 April 2008.
  76. ^ "calc() as CSS unit of measurement value". Tin I use... Support tables for HTML5, CSS3, etc. CanIUse.com. Archived from the original on 2016-03-04.
  77. ^ "CSS Multi-column Layout Module". Earth Broad Spider web Consortium. Archived from the original on 2011-04-29. Retrieved 2011-05-01 .
  78. ^ "Tin can I use... Support tables for HTML5, CSS3, etc". CanIUse.com. Archived from the original on 2010-08-21. Retrieved 2016-02-27 .
  79. ^ Cederholm, Dan; Ethan Marcotte (2009). Handcrafted CSS: More Bulletproof Web Design. New Riders. p. 114. ISBN978-0-321-64338-4. Archived from the original on 20 December 2012. Retrieved 19 June 2010.
  80. ^ Antti, Hiljá. "OOCSS, ACSS, BEM, SMACSS: what are they? What should I utilize?". clubmate.fi. Hiljá. Archived from the original on 2 June 2015. Retrieved 2 June 2015.

Further reading [edit]

  • Jeffrey Zeldman (2009): Designing With Spider web Standards, New Riders, ISBN 978-0321616951 (paperback) (book's companion site)
  • Dan Cederholm (2009): Web Standards Solutions, The Markup and Manner Handbook, Friends of Ed, ISBN 978-1430219200 (paperback) (Author's site)
  • Meyer, Eric A. (2006). Cascading Style Sheets: The Definitive Guide, Tertiary Edition. O'Reilly Media, Inc. ISBN0-596-52733-0.
  • More Eric Meyer On CSS (2004) ISBN 0-7357-1425-8
  • Eric Meyer On CSS (2002), ISBN 0-7357-1245-X
  • Meyer, Eric A. (2001) Cascading Fashion Sheets 2.0 Programmer'southward Reference, McGraw-Colina Osborne Media, ISBN 0-07-213178-0
  • The Zen of CSS Design (2005) (co-authored by CSS Zen Garden Owner, Dave Shea, and Molly E. Holzschlag), ISBN 0-321-30347-4
  • Kynn Bartlett: Teach Yourself CSS in 24 Hours, 2nd Edition (2006), Sams Publishing, ISBN 978-0672329067
  • Cascading Style Sheets: Designing for the Web (2005) past Håkon Wium Prevarication and Bert Bos, ISBN 0-321-19312-i
  • Cascading Way Sheets Cascading Style Sheets, PhD thesis, by Håkon Wium Lie – provides an authoritative historical reference of CSS
  • Keith Schengili-Roberts (2003): Cadre CSS, second Edition, Prentice Hall, ISBN 0-13-009278-9
  • On the Analysis of Cascading Style Sheets, Pierre Geneves, Nabil Layaida, and Vincent Quint, Proceedings of the 21st International Briefing on World wide web (WWW'12), pp. 809–818, 2012.

External links [edit]

  • Official website Edit this at Wikidata
  • CSS at Curlie

wallaccom1989.blogspot.com

Source: https://en.wikipedia.org/wiki/CSS

0 Response to "Html and Css3 Second Edition Unit J Concepts Review"

Postar um comentário

Assinar: Postar comentários (Atom)

Iklan Atas Artikel

Iklan Tengah Artikel 1

Iklan Tengah Artikel 2

Iklan Bawah Artikel