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XHTML and CSS. Overview. Hypertext Markup Language. A set of markup tags and associated syntax rules Unlike a programming language, you cannot describe actions or logic You can only describe information structure and context Markup tags also called elements

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Xhtml and css



Hypertext markup language

Hypertext Markup Language

  • A set of markup tags and associated syntax rules

  • Unlike a programming language, you cannot describe actions or logic

  • You can only describe information structure and context

  • Markup tags also called elements

  • <element>Data goes here</element>

Cascading style sheets

Cascading Style Sheets

  • Used to define attributes of elements in HTML and XML

    • Common attributes: height, width, font-size, alignment, color, etc.

  • Documents can have multiple style sheets with overlapping and sometimes conflicting definitions

  • Cascading refers to the set of rules for resolving conflicts.



  • Priority is given to the most specific definitions and then the definitions or rules cascade down to the less specific rules.

  • Priority is also given to definitions that are “closer” to the content, i.e., embedded and inline styles can be used to override global or attached styles.

Xhtml css syntax

General Structure



element {

attribute: value;

attribute: value;



h1 {

font-size: 10pt;

color: red;


XHTML & CSS syntax

Extensible html xhtml

Extensible HTML  XHTML

  • XHTML is a reformulation of HTML according to XML standards.

  • Only four differences

    • Inclusion of an XML header

    • Single tags end with />, instead of just >

    • Attribute values must have quotes: “value”

    • Tags must be in lowercase

Why use xhtml

Why use XHTML?

  • It is the recommended standard (W3C) since 2000

    • HTML 4.01 (1999)

    • XHTML 1.0 (2000)

  • Allows your web page to be parsed by a general XML parser.

    • Lots of applications support XML parsing.

Web s 4 commandments

Web’s 4 Commandments

  • Make sure your code validates as XHTML

  • Use Semantic Markup

    • Use tags that describe the content, not the content’s appearance

  • Structure Documents Logically

    • The HTML code should be in a logical order; Style sheets can reposition items for presentation

  • Use CSS, not <font> or <table> to layout and decorate your pages.

Xhtml rules


<elementname> Content content</elementname>

  • In XHTML all element names must be lower case.

    • In HTML tag case didn’t matter.

  • In XHTML all element must have a closing tag

    • Most web browsers are forgiving about closing tags, which makes it possible to forget about them

    • Example <p>Here is paragraph with no ending tag<p>Here is another paragraph</p>

Html single tags

HTML single tags

  • HTML has a few tags that are standalone, i.e., no closing tag.

  • Image: <imgsrc=“imagename.jpg”>

  • Line break: <br>

  • Link: <link type="text/css”>

    • Used to link/insert a Cascading Style Sheet

Xhtml single tags

XHTML single tags

  • To meet XML guidelines HTML single tags must to closed with a />

  • Image: <imgsrc=“imagename.jpg” />

  • Line break: <br />

  • Link: <link type="text/css" />

  • Note the space before the />



<element attribute=“value”> content </element>

XHTML requires that all attribute values be enclosed in quotes.

HTML: <imgsrc=tiger.jpg>

XHTML: <imgsrc=“tiger.jpg” />

Forgiving browsers don’t care about the quotes (Follow XHTML; quotes matter to us)

Browsers ignore whitespace

Browsers ignore whitespace

  • An XHTML document is an ASCII Text document.

  • XHTML renderers ignores, tabs, spaces and line breaks

    • Allows a web designer to format XHTML code without having an effect on the web page’s rendered appearance.

  • To render tabs, spaces, and line breaks requires using tags and style sheets.

Basic xhtml document

Basic XHTML document

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN…

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">


<title> Title Displays in Browser’s Top Bar </title>

<link type="text/css" href="part5.css" rel="stylesheet"/>



Page content here



Text structure blocks

Text Structure (blocks)

<h1>Most Important Header</h1>

<p>A paragraph in the literal sense.</p>


<h3>Smaller Sub-heading</h3>

<h6>Smallest Sub-heading</h6>


Ordered Lists (ol)

Unordered Lists (ul)


<li>Item 1</li>

<li>Item 2</li>

<li>Item 3</li>

<li>Item 4</li>



<li>Item 1</li>

<li>Item 2</li>

<li>Item 3</li>

<li>Item 4</li>



Terms and definitions





<dd>black hot drink</dd>


<dd>white cold drink</dd>


dl – definition list

dt – definition term

dd – definition description

Used heavily in early HTML documents which were most scientific papers with lost of definitions and terms

Terms and Definitions

Text formatting style

Text Formatting (style)

<tt> Teletype text </tt>

<i> Italic text </i>

<b> Bold text </b>

<big> Big text </big>

<small> Small text </small>

Text identity semantic

Text identity (semantic)

<em> Emphasized text </em>

<strong> Strong text </strong>

<dfn> Definition term </dfn>

<code> Computer code text </code>

<samp> Sample computer code </samp>

<kbd> Keyboard text </kbd>

<var> Variable </var>

<cite> Citation </cite>



  • Called the anchor tag

    <a href=“http://www.espn.com”>ESPN</a>

  • href stands for hypertext reference

  • What is the element name?

  • What is the attribute?

  • What is the attribute’s value

  • What is the content?

Elements we ll learn about later

Elements we’ll learn about later







<form action=“program.php”>

<input type=“text”>

<input type=“submit”>



  • Deprecated!



  • Removed from the standard

  • Most browsers will still render deprecated tags

  • However, there are no guarantees

  • Do not use deprecated tags unless you have no choice

Divisions and spans

Divisions and Spans

  • Divisions <div> used to break your webpage into logical blocks or boxes

  • Spans<span> used to create custom in-line tags, i.e., within the flow of a paragraph of text.


  • This is paragraph with a table reference. <span class=“tableref”>Table 2.4</span> is a lovely table.

Css attributes


BOXES (usually <div> elements)

  • Font family,

  • size,

  • alignment,

  • weight,

  • sytle,

  • variant,

  • line-height,

  • indent, spacing,

  • direction

  • Height,

  • width,

  • margins,

  • padding,

  • borders,

  • border color,

  • border styles,

  • background color,

  • background image.

CSS Attributes

Xhtml and css


  • Best way to learn is by example.

  • Let’s take a peak at the lab.

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