xhtml_intro

viraginitysplashInternet and Web Development

Nov 10, 2013 (3 years and 7 months ago)

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1

HTML/XHTML Objectives


Explain what HTML is and how Web pages use
HTML


Demonstrate how to create Web pages with
nothing more than a text editor and a browser


Explore the role of HTML standards on the Web


Tags of HTML/XHTML


Focus on XHTML


Will mention differences

2

To Create a Web Site

You Need


Computer with modem or telecommunication
devices


A text editor (or Web page construction kit)


Notepad


Free
http://fixedsys.com/context/

http://www.context.cx/component/option,com_docman/Itemid,48/


An Internet access account


A password
-
protected account on a Web server

3

Uniform Resource Locator

(URL)


All Web pages are addressed with
URLs


The URL specifies


A server name www.uwosh.edu


A directory path faculty_staff/huen


A filename home.html


URLs are part of the HTTP (Hypertext
Transfer Protocol) communications
protocol.

4

Web Page Displays


All browsers are designed to display
files with .html and .htm extensions


Web pages can look a little different
on different computers


Web page authors cannot completely
control their page displays

5

The Hypertext Markup
Language (HTML)


HTML formatting commands
control Web page displays


All HTML formatting is achieved
with HTML
elements


All HTML
elements

are based on
HTML tags and tag
-
pairs


HTML files can be created with text
editors

6

A HTML TagTemplate

<html>


<head>



<title>




(insert text for the browser’s title bar
here)



</title>


</head>


<body>




(insert visible Web page elements here)


</body>

</html>

7

HTML Editors


Example: Homesite
(Macromedia/Coldfusion)


Pros


Offer lots of useful features


Help you avoid tagging errors


Can save time


Cons


Can interfere with HTML mastery


8

The Web Page

Development Cycle

1. Save your HTML file

2. Load the file into your Web browser

3. Review the file with your Web browser

4. Validate your HTML script

5. Revise your HTML file with a text editor


Repeat this cycle as often as needed

9

Non
-
Standard HTML


Browser vendors create their own HTML
extensions to influence the industry
standard


Browser
-
specific: Some vendor provide
HTML tags extensions specific to their own
product


Netscape Navigator and IE do not always
recognize each other’s HTML extensions


Web pages that use non
-
standard HTML
may not display well for all users

10

Origins and Evolution of HTML


HTML was defined with SGML (Standard
Generalized Markup Language)


Original intent of HTML: General layout of
documents displayable by a wide variety of
computers


Recent versions:


HTML 4.0


1997


Many new features and deprecated many older
features


HTML 4.01
-

1999
-

A cleanup of 4.0


11

Browser War


User’s experience varies with the browser


Developers need to provide multiple
versions of a page


Standardization began with HTML 3.2


HTML 4 and CSS


Separate structure and format


XML to add new features


XML: language to create new languages

12

XML


Labeled data reusable


Price paid


Case sensitive


Quotation marks


Closing tags


Backward compatible with HTML?


Rewrite HTML in XML


Developers learn basic syntax rules


So xhtml is born

13

Evolution of HTML


XHTML 1.0


2000


Reformulate HTML 4.01 in XML,
instead of SGML


Will follow XHTML 1.0 Strict


XHTML 1.1


2001


Modularize 1.0, and drops frames


Very similar to XHTML Strict



14

Industry Standards


Most HTML tags are in the official
HTML standard


All HTML
-
compliant browsers
recognize the standard HTML tag set


The World Wide Web Consortium
(W3C) sets the industry standard for
HTML
http://www.w3c.org

15

HTML Validation Services


Validation services on the Web can check an
HTML file for you


http://validator.w3.org/file
-
upload.html


(recommended, free, official)


http://www.netmechanic.com/

(commercial)


http://www.htmlhelp.com/tools/validator/

(commercial)


To identify tagging errors and HTML
extensions


Some HTML tagging errors are difficult to
locate by manual inspection


Without an HTML editor, a validation service
can be very helpful

16

Shortcut


Use
xhtml

template


See template.html