xp tutorial 7new perspectives on html and xhtml, comprehensive 1 working with cascading style sheets...

Tutorial 7 New Perspectives on HTML and XHTML, Comprehensive

1

XP

Working with Cascading Style Sheets

Tutorial 7


2

XPUsing Inline StylesSession 7.1

• Inline styles are easy to use and interpret because they are applied directly to the elements they affect.

<element style=“style1: value1; style2:value2; style3: value3;…”>

<h1 style=“text-align: center; font-family: Arial, Helvetica, sans-serif”>


3

XPUsing Embedded Styles

• You can embed style definitions in a document head using the following form:

<style>style declarations

</style>

Where style declarations are the declarations of the different styles to be applied to the document.


4

XPUsing an External Style Sheet

• Because an embedded style sheet only applies to the content of the file it is embedded in, you need to place style declarations in an external style sheet to apply to the rest of the Web site.

• An external style sheet is a text file that contains style declarations.– It can be linked to any page in the site, allowing the

same style declaration to be applied to the entire site


5


• You can add style comments as you develop an external style sheet.– /* comment */

• Use the link element to link a Web page to an external style sheet.<link href=“name.css” rel=‘stylesheet” type =

“text/css” />


6


• You can import the content of one style sheet into another.

• Add the following to either an embedded or an external style sheet– @import(name.css);


7

XPUnderstanding Cascading Order

• You can link a single style sheet to multiple documents in your Web site by using the link element or the @import element.

• You can also link a single document to several style sheets.


8

XPApplying a single style sheet to multiple documents


9

XPApplying multiple sheets to a single document


10

XPStyle Precedence

1. External style sheet

2. Embedded styles

3. Inline styles


11

XPStyle Precedence

• If two styles have the same weight then the one declared last has precedence.<style type=“text/css”>

H1 {color: orange; font-family: sans-serif”}

H1{color: blue; font-family: serif}

</style>


12

XPStyle Precedence

• You can override the precedence rules by adding the !important property to a style declaration<style type=“text/css”>

H1 {color: orange !important; font-family: sans-serif”}H1{color: blue; font-family: serif}

</style>Gives the orange colour precedence


13

XPStyle Inheritance

• If a style is not specified for an element, it inherits the style of its parent element. This is called style inheritance.– Causes style declarations to cascade down

through a document’s hierarchy

• To set every element on a page to blue– Body {color: blue}

• Every element on the page inherits this style


14

XPStyle Inheritance

• To override style inheritance you specify an alternate style for one of the descendent elements of the parent.– Body {color: blue}

– P {color: red}

– Changes every element on the page to blue except for paragraphs and every element within a paragraph

• !important property also overrides style inheritance


15

XPWorking with Selectors

• CSS allows you to work with a wide variety of selectors to match different combinations of elements.– h1, h2, h3 {font-family: sans-serif}– h1 {color: blue}– h2 {color: red}

• h1 headings are blue sans-serif• h2 headings are red sans-serif.


16

XPWorking with Selectors

• Set all bold text to blue – b {color: blue }

• Use contextual selectors to apply a style based on the context in which an element is used.

• Eg, to apply a style to text within a list– li b {color: blue}

• li is the parent element, b is the descendant element


17

XPSimple and contextual selectors


18

XPAttribute Selectors

• Create an attribute selector to select an element based on the element’s attributes.– a {color: blue} – all <a> tags

– a[href] {color: blue} – only hrefs, not anchors

– See figure 7-13 in your text for a list of attribute selectors


19

XPUsing IDs and ClassesSession 7.2

• Use an id to distinguish something, like a paragraph, from the others in a document.– For example, to identify a paragraph as

“head”, use the code:

<p id=“head”>… </p>


20

XPClasses

• HTML and XHTML require each id be unique– therefore an id value can only be used once in a document.

• You can mark a group of elements with a common identifier using the class attribute.

<element class=“class”> … </element>


21

XPApplying a style to a class


22

XPApplying a style to a class and element


23

XPSizing Elements and Floating an Element

• You can define the width of columns in a columnar layout using: width: value

• You can use CSS to set an element’s height using: height: value

• You can float a paragraph using: float: position


24

XPWorking with the div Element

• The div element is a generic block-level element.

<div>

content

</div>


25

XPSetting the Display Style

Values of the display style


26

XPSetting the Display Style

Values of the display style


27

XPWorking with the Box Model

• The box model is an element composed of four sections:– Margin– Border– Padding– content


28

XPThe Box Model


29

XPWorking with the Box Model

• Styles to set padding are similar to styles to set margins:– padding-top: value– padding-right: value– padding-bottom: value– padding-left: value


30

XPBorder Styles


31

XPBorder Style Types


32

XPUsing Pseudo-Classes and Pseudo-Elements

• A pseudo-class is a classification of an element based on its status, position, or current use in the document.


33

XPUsing Pseudo-Classes and Pseudo-Elements

• Rollover effects can be created using pseudo-classes.

• Pseudo-elements are elements based on information about an element’s content, use or position.


34

XPPositioning Objects with CSSSession 7.3

• The different positioning styles in the original CSS1 specifications were known as CSS-Positioning or CSS-P.

• To place an element at a specific position on a page use:

position: type; top: value; right: value;

bottom: value; left: value;


35

XPWorking with Overflow and Clipping

• The overflow property syntax:overflow: type


36

XPStacking Elements

• Specify stacking order with:z-index: value

z-index: 3

z-index: 1

z-index: 2


37

XPWorking with Different Media

• Specify output styles for particular devices in the media attribute of the link and style elements


38

XPThe @media Rule

• You can also specify the output media within a style sheet using:

@media type {style declarations}

Where media is one of the supported media types

and style declarations are the styles

associated with that media type.


39

XPMedia Groups

• CSS2 uses media groups to describe basic facets of different media– and to differentiate between different types of media based on the ways they render content.– Continuous or paged– Visual, aural, or tactile– Grid (for character grid devices) or bitmap– Interactive or static


40

XPMedia Groups


41

XPHiding Elements

• Two different styles that allow you to hide elements:– Display style– Visibility style


42

XPComparing the visibility and display styles

Visibility hidden

Object is hidden but still is part of the page flow

Display: none

Object is hidden and is removed from the page flow


43

XPUsing Print Styles

• You can specify the size of a page, margins, internal padding, etc. of the page box.

• Review the Reference Window on page HTML 420 for working with print styles.

xp tutorial 7new perspectives on html and xhtml, comprehensive 1 working with cascading style sheets...

Documents