Shyam sunder Rajasthan Computer

Introduction Introduction To CSSTo CSS

by: by: Alexandra VlachakisAlexandra VlachakisSandy Creek High School, Fayette County SchoolsSandy Creek High School, Fayette County Schools

Content and Resources Used With Permission: Content and Resources Used With Permission: Interact With Web Standards. Copyright 2010. Erin Anderson et. Al.Interact With Web Standards. Copyright 2010. Erin Anderson et. Al.

W3 Schools. www.w3schools.com. 12-25-11. W3 Schools. www.w3schools.com. 12-25-11.

mailto:[email protected]

HTML ReviewHTML Review

► What is HTML used for?► Give some examples of formatting tags in

HTML?► HTML is the most widely used language on the

Web► In today’s lesson we will be discussing the

second most widely used language on the web► Does anyone know the name of the second most

widely used language?

Lesson 1: History of CSSLesson 1: History of CSS

► CSS was proposed in 1994 as a web styling language. To helps solve some of the problems HTML 4.

► There were other styling languages proposed at this time, such as Style Sheets for HTML and JSSS but CSS won.

► CSS2 became the recommendation in 1998 by W3C

► CSS3 was started in 1998 but it has never been completed. Some parts are still being developed and some components work on some browsers.

Lesson 1: What is CSS?Lesson 1: What is CSS?• CSSCSS stands for stands for CCascading ascading SStyle tyle SSheets heets • Styles - define Styles - define how to displayhow to display HTML elements HTML elements • Styles are normally stored in Styles are normally stored in Style SheetsStyle Sheets

Definition:Definition:Cascading Style Sheets (CSS) – is a rule based language that applies styling to your HTML elements. You write CSS rules in elements, and modify properties of those elements such as color, background color, width, border thickness, font size, etc.

Lesson 1: Examples of Lesson 1: Examples of CSSCSS

► Example 1: Example 1: http://www.csszengarden.com/http://www.csszengarden.com/► Example 2: Example 2: http://w3schools.com/css/demo_default.htmhttp://w3schools.com/css/demo_default.htm ► If you notice each time we click on a different CSS style sheet on the If you notice each time we click on a different CSS style sheet on the

two pages above the look and feel of each page changes dramatically two pages above the look and feel of each page changes dramatically but the content stays the same.but the content stays the same.

► HTML did not offer us this option.HTML did not offer us this option.► HTML was never intended to contain tags for formatting a document.HTML was never intended to contain tags for formatting a document.► HTML was intended to define the content of a document, like:HTML was intended to define the content of a document, like:► <h1>This is a heading</h1><h1>This is a heading</h1>► <p>This is a paragraph.</p><p>This is a paragraph.</p>► When tags like <font>, and color attributes were added to the HTML When tags like <font>, and color attributes were added to the HTML

3.2 specification, it started a nightmare for web developers. 3.2 specification, it started a nightmare for web developers. Development of large web sites, where fonts and color information Development of large web sites, where fonts and color information were added to every single page, became a long and expensive were added to every single page, became a long and expensive process.process.

► To solve this problem, the World Wide Web Consortium (W3C) created To solve this problem, the World Wide Web Consortium (W3C) created CSS.CSS.

http://www.csszengarden.com/

http://w3schools.com/css/demo_default.htm

HTML Formatting ReviewHTML Formatting Review

► What are the starting tags in HTML?What are the starting tags in HTML?► What are the ending tags in HTML?What are the ending tags in HTML?► How do you save in a Notepad document so it How do you save in a Notepad document so it

becomes a web page?becomes a web page?► What is the tag for creating paragraphs in What is the tag for creating paragraphs in

HTML?HTML?► What is the tag for creating heading tags in What is the tag for creating heading tags in

HTML?HTML?► What are the tags we use to format font: family, What are the tags we use to format font: family,

color, size, alignment in HTML?color, size, alignment in HTML?

Lesson 2: Lesson 2: Syntax oF CSSSyntax oF CSS The CSS syntax is made up of 5 parts: The CSS syntax is made up of 5 parts:

selectorselector property/valueproperty/value declaration declaration declaration block declaration block curly bracescurly braces

We will explore each part in the next slides.We will explore each part in the next slides.

SelectorSelector

Definition: identifies the HTML elements that the Definition: identifies the HTML elements that the rule will be applied to, identified by the actual rule will be applied to, identified by the actual element name, e.g. <body>, or by other means element name, e.g. <body>, or by other means such as such as classclass attribute values. attribute values.

Example:Example:

*The selector is normally the HTML element you want to style

Property & ValueProperty & Value

Definition: Definition: The property is the style attribute you want to change. Each property has a value.

*Properties are separated from their respective values by *Properties are separated from their respective values by colons colons ::*Pairs are separated from each other by Pairs are separated from each other by semicolons semicolons ;;

DeclarationDeclaration

Definition: Each CSS line that includes property Definition: Each CSS line that includes property and valueand value

*Each declaration consists of a property and a value.

Declaration BlockDeclaration Block

Definition: multiple declaration lines including the Definition: multiple declaration lines including the curly bracescurly braces

Curly BracesCurly Braces

Definition: the curly braces contain the Definition: the curly braces contain the properties of the element you want to properties of the element you want to manipulate, and the values that you want to manipulate, and the values that you want to change them to. The curly braces plus their change them to. The curly braces plus their content is called a declaration block. content is called a declaration block.

Example:Example:

Lesson 2 Assignment:Lesson 2 Assignment:Let’s Create Our First CSS PageLet’s Create Our First CSS Page

► Open NotepadOpen Notepad► Type the following CodeType the following Code

<html><html><head><head><style type="text/css"><style type="text/css">p {color:red; text-align:center;} p {color:red; text-align:center;}

</style></style></head></head>

<body><body><p>Hello World!</p><p>Hello World!</p><p>This paragraph is styled with CSS.</p><p>This paragraph is styled with CSS.</p></body></body></html></html>

► Save Your File as css-myfirstpage.html into a new folder called CSSSave Your File as css-myfirstpage.html into a new folder called CSS

►Instructor Note: You can Instructor Note: You can demonstrate how to do this by demonstrate how to do this by using the using the example given on the example given on the W3schools site. Also as you are W3schools site. Also as you are creating this file point out to creating this file point out to students where they will find the students where they will find the different syntax found in CSS.different syntax found in CSS.►After creating the file have After creating the file have students manipulate the color and students manipulate the color and alignment values.alignment values.

http://www.w3schools.com/css/tryit.asp?filename=trycss_syntax1

Lesson 3: Lesson 3: Class and id Class and id SelectorsSelectors In addition to setting a style for a HTML element, CSS allows In addition to setting a style for a HTML element, CSS allows

you to specify your own selectors called "id" and "class".you to specify your own selectors called "id" and "class".

idid - - The id selector is used to specify a style for a single, unique The id selector is used to specify a style for a single, unique element. element.

The id selector uses the id attribute of the HTML element, The id selector uses the id attribute of the HTML element, and is defined with a "#". and is defined with a "#".

The style rule below will be applied to the element with The style rule below will be applied to the element with id="para1": id="para1":

#para1 {text-al ign:center;color:red;}#para1 {text-al ign:center;color:red;}

Lesson 3: Lesson 3: Class and id Class and id SelectorsSelectorsClass Class -- The class selector is used to specify a style for a group The class selector is used to specify a style for a group

of elements. Unlike the id selector, the class selector is most of elements. Unlike the id selector, the class selector is most often used on several elements. often used on several elements.

This allows you to set a particular style for any HTML This allows you to set a particular style for any HTML elements with the same class. elements with the same class.

The class selector uses the HTML class attribute, and is The class selector uses the HTML class attribute, and is defined with a "." defined with a "."

In the example below, all HTML elements with class="center" In the example below, all HTML elements with class="center" will be center-aligned:will be center-aligned:

.center {text-align:center;}.center {text-align:center;}

Lesson 3: Lesson 3: Class and id Class and id SelectorsSelectors

In the image below what is the h1 selector In the image below what is the h1 selector an ID or a Class?an ID or a Class?

#

.

Lesson 3 Assignment:Lesson 3 Assignment:Let’s Create A CSS Page that uses “id”Let’s Create A CSS Page that uses “id”


<html><head><style type="text/css">#para1{text-align:center;color:red;} </style></head>

<body><p id="para1">Hello World!</p><p>This paragraph is not affected by the style.</p></body></html>

► Save Your File as css-id.html into a your folder called CSS.Save Your File as css-id.html into a your folder called CSS.

►Instructor Note: You can Instructor Note: You can demonstrate how to do this by demonstrate how to do this by using the using the example given on the example given on the W3schools site. Also as you are W3schools site. Also as you are creating this file point out to creating this file point out to students where they will find the students where they will find the different syntax found in CSSdifferent syntax found in CSS►After creating the file have After creating the file have students manipulate the name of students manipulate the name of the “id”the “id”

http://www.w3schools.com/css/tryit.asp?filename=trycss_syntax_id

Lesson 3 Assignment:Lesson 3 Assignment:Let’s Create A CSS Page that uses “class”Let’s Create A CSS Page that uses “class”


<html><head><style type="text/css">.center{text-align:center;}</style></head>

<body><h1 class="center">Center-aligned heading</h1><p class="center">Center-aligned paragraph.</p> </body></html>

► Save Your File as css-class.html into a your folder called CSS.Save Your File as css-class.html into a your folder called CSS.

►Instructor Note: You can Instructor Note: You can demonstrate how to do this by demonstrate how to do this by using the using the example given on the example given on the W3schools site. Also as you are W3schools site. Also as you are creating this file point out to creating this file point out to students where they will find the students where they will find the different syntax found in CSSdifferent syntax found in CSS►After creating the file have After creating the file have students manipulate the name of students manipulate the name of the “class”the “class”

http://www.w3schools.com/css/tryit.asp?filename=trycss_syntax_class

Lesson 3 CommentsLesson 3 Comments► Comments are used to explain your code, and may help you when you edit Comments are used to explain your code, and may help you when you edit

the source code at a later date. Comments are ignored by browsers.the source code at a later date. Comments are ignored by browsers.

► You add comments by enclosing them inYou add comments by enclosing them in /* and *//* and */

► Comments can span several lines, and the browser will ignore these lines.Comments can span several lines, and the browser will ignore these lines.

► Example:Example:

► /* This is a basic comment it will not appear on the page*/ /* This is a basic comment it will not appear on the page*/ /* starts the comment /* starts the comment */ is the end of the comment*/ is the end of the comment

/*This is a comment*//*This is a comment*/p{ text-align:center; color:black; font-family:arial;}p{ text-align:center; color:black; font-family:arial;}

Lesson 3 Assignment:Lesson 3 Assignment:Let’s Add A CommentLet’s Add A Comment

► Open Your CSS-ID example in NotepadOpen Your CSS-ID example in Notepad► Type the following Code right above the style you had written previously.Type the following Code right above the style you had written previously.

<html><head>/*This is an example of how to use ID in a CSS web page*//*This is an example of how to use ID in a CSS web page*/

<style type="text/css">#para1{text-align:center;color:red;} </style></head>

<body><p id="para1">Hello World!</p><p>This paragraph is not affected by the style.</p></body></html>

► Save Your File as css-comment.html into a your folder called CSS.Save Your File as css-comment.html into a your folder called CSS.

Lesson 4:Lesson 4: How CSS is Applied to A Web How CSS is Applied to A Web PagePage

►CSS is applied to a web page using three CSS is applied to a web page using three different methods:different methods: Inline styleInline style Internal style sheetInternal style sheet External style sheet External style sheet

► Inline CSSInline CSS►Applies styles directly to the elements by Applies styles directly to the elements by

adding declarations into the styleadding declarations into the style►For Example:For Example:<p style=“color: red;”> This is a simple <p style=“color: red;”> This is a simple

paragraph and the inline style makes it paragraph and the inline style makes it red.</p>red.</p>


► Internal Style SheetInternal Style Sheet► Applies styles to HTML by placing the CSS rules inside the tag Applies styles to HTML by placing the CSS rules inside the tag

<style> inside the document tag <head>.<style> inside the document tag <head>.► For Example:For Example:<head><head><title>my page</title><title>my page</title><style type=“text/css”><style type=“text/css”>p{color:red}</style>p{color:red}</style></head></head><body><body><p>this is a simple paragraph<p>this is a simple paragraph</p></p></body></body>


► External CSSExternal CSS► Applies styles as a separate file with a .css extension. The file is Applies styles as a separate file with a .css extension. The file is

then referenced from inside the <head> element by a link to the then referenced from inside the <head> element by a link to the file.file.

► For Example:For Example:<head><head><title>my external style sheet page</title><title>my external style sheet page</title><link rel=“style sheet” type=“text/css” href=“my-external-<link rel=“style sheet” type=“text/css” href=“my-external-

stylesheet.css”>stylesheet.css”><body><body><p>this is a simple paragraph</p><p>this is a simple paragraph</p></body></body>► You can create an external style sheet in your text editor.You can create an external style sheet in your text editor.


► What style sheet is best?What style sheet is best?► Web developers rarely use inline CSS. Since they prefer Web developers rarely use inline CSS. Since they prefer

to not mix content with presentation. And it is not to not mix content with presentation. And it is not efficient since you have to declare the style individually efficient since you have to declare the style individually for every component.for every component.

► Internal and External style sheets are more popular Internal and External style sheets are more popular because you can style multiple elements with one rule.because you can style multiple elements with one rule.

► External style sheets are best because they allow you to External style sheets are best because they allow you to save all the style information on a separate file from the save all the style information on a separate file from the content. You can then modify a style for a site and it will content. You can then modify a style for a site and it will update all of the pages in a site.update all of the pages in a site.


►CSS ColorsCSS Colors► In the previous lesson you have seen a few In the previous lesson you have seen a few

CSS styles that included color like: <p CSS styles that included color like: <p style=“color: red;”> style=“color: red;”>

►There are a few ways that you can set There are a few ways that you can set colors in CSS:colors in CSS:

Keywords, Hex values, RGB, HSL(a)Keywords, Hex values, RGB, HSL(a)

Lesson 5:Lesson 5: Colors and Formatting in CSS Colors and Formatting in CSS

►CSS Colors: KeywordsCSS Colors: Keywords►Using the keywords like: red, fuchsia, yellow, Using the keywords like: red, fuchsia, yellow,

blue, green you can specify what color you would blue, green you can specify what color you would like the CSS rule to display.like the CSS rule to display.

► For example:For example:► p{color:red}p{color:red}► h2{color:yellow}h2{color:yellow}► There are 17 of these keyword colors you can There are 17 of these keyword colors you can

use in CSS. use in CSS.


Keyword ColorKeyword Color HexHex

aqua #00ffff

black #000000

blue #0000ff

fuchsia #ff00ff

gray #808080

green #008000

lime #00ff00

maroon #800000

navy #000080

olive #808000

orange (added in CSS 2.1) #ffa500

purple #800080

red #ff0000

silver #c0c0c0

teal #008080

white #ffffff

yellow #ffff00


►Computers are capable of displaying a lot more Computers are capable of displaying a lot more than 17 colors.than 17 colors.

► In fact they can display approximately 16.7 In fact they can display approximately 16.7 million colors!million colors!

►Hex Values (hex is short for hexadecimal) are Hex Values (hex is short for hexadecimal) are the most common way of specifying colors for the most common way of specifying colors for web pages. (see hex# in the previous chart)web pages. (see hex# in the previous chart)

► For example: For example: p{color: #000000;}p{color: #000000;}/*This is equivalent to the keyword black*//*This is equivalent to the keyword black*/


►Hex numbersHex numbers - has 16 possible values - has 16 possible values►0 to 9 then A to F. Which gives you 16 0 to 9 then A to F. Which gives you 16

values.values.►RGB (Red Green Blue) has the possibility RGB (Red Green Blue) has the possibility

of 256 colors for each (16x16)of 256 colors for each (16x16)►(R)256 x (G)256 x (B)256 = 16,777,216 or (R)256 x (G)256 x (B)256 = 16,777,216 or

16.7 million color values16.7 million color values►CSS example: h1{color: #000000;}CSS example: h1{color: #000000;}


►RGB (a)RGB (a) can also help specify colors in CSS can also help specify colors in CSS RGB stands for Red Green BlueRGB stands for Red Green Blue

►You can specify RGB in either whole numbers or You can specify RGB in either whole numbers or percentagespercentages

►CSS example: h1{color: rgb(0,0,0) }CSS example: h1{color: rgb(0,0,0) }/*this color is equivalent to #000000 or black *//*this color is equivalent to #000000 or black */►You use numbers from 0 to 255 which covers the You use numbers from 0 to 255 which covers the

256 color range.256 color range.►More examples can be found at: More examples can be found at:

http://www.w3schools.com/css/css_colors.asphttp://www.w3schools.com/css/css_colors.asp


http://www.w3schools.com/css/css_colors.asp

► RGB (a)RGB (a) can also help specify colors in CSS RGB can also help specify colors in CSS RGB stands for Red Green Blue. The “a” stands for alpha but stands for Red Green Blue. The “a” stands for alpha but we will learn about that in another lesson.we will learn about that in another lesson.

► You can specify RGB in either whole numbers or You can specify RGB in either whole numbers or percentagespercentages

► CSS example: h1{color: rgb(0,0,0) }CSS example: h1{color: rgb(0,0,0) }/*this color is equivalent to #000000 or black *//*this color is equivalent to #000000 or black */► You use numbers from 0 to 255 which covers the 256 You use numbers from 0 to 255 which covers the 256

color range.color range.► More examples can be found at: More examples can be found at:

http://www.w3schools.com/css/css_colors.asphttp://www.w3schools.com/css/css_colors.asp


http://www.w3schools.com/css/css_colors.asp

►HSL (a)HSL (a) - Hue Saturation Lightness - Hue Saturation Lightness►Similar to RGB but based on saturation and Similar to RGB but based on saturation and

lightness of a colorlightness of a color► The “a” stands for alpha but we will learn about The “a” stands for alpha but we will learn about

that in another lesson.that in another lesson.►CSS example: h1{color: hsl(0,100%,40%) }CSS example: h1{color: hsl(0,100%,40%) }►HSL accepts a number between 0 to 360 in valueHSL accepts a number between 0 to 360 in value►HSL also accepts percentage between 0-100%HSL also accepts percentage between 0-100%


Lesson 5 Assignment:Lesson 5 Assignment:CSS Using ColorCSS Using Color

► Open Your CSS-ID example in NotepadOpen Your CSS-ID example in Notepad► Type the following Code right above the style you had written previously.Type the following Code right above the style you had written previously.

<html><body>

<p style="background-color:#FFF111">Color set by using hex value</p>

<p style="background-color:rgb(0,255,0);">Color set by using rgb value</p>

<p style="background-color:red">Color set by using color name</p>

</body></html>► Save Your File as css-color.html into your folder called CSSSave Your File as css-color.html into your folder called CSS

►Instructor Note: You can Instructor Note: You can demonstrate how to do this by demonstrate how to do this by using the using the example given on the example given on the W3schools site. Also as you are W3schools site. Also as you are creating this file point out to creating this file point out to students the different syntax found students the different syntax found in CSS.in CSS.►After creating the file have After creating the file have students manipulate the color students manipulate the color values to discover other color values to discover other color combinations.combinations.

http://www.w3schools.com/css/tryit.asp?filename=trycss_colorhex

►Essential Questions ReviewEssential Questions Review

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Shyam sunder Rajasthan Computer