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HTML & CSS:The Complete Reference,Fifth Edition

About the AuthorThomas A. Powell (tpowell@pint.com) is a long-timeindustry veteran. After an early stint at CERFnet in theearly ‘90s, he founded Powell Internet Consulting (laterrenamed PINT) in 1994, a Web design and consulting servicesfirm. Today, PINT (pint.com) provides Web development,design, and consulting services to large and small corporationsall over the United States in a variety of industries.Beyond his involvement at PINT, Thomas is heavilyinvolved in the academic community. He developed theUniversity of California, San Diego Extension Web Publishingprogram in the late 1990s and continues to teach classes therein Web development and design. He is also an instructor forthe UCSD Computer Science Department, where he teachesclasses in Web development and the theory of programminglanguages.Mr. Powell is well published, and his work has appearedin numerous trade publications. He continues to publishregularly in Network World. He also has published numerousbooks on Web technology and design, including Ajax: TheComplete Reference, JavaScript: The Complete Reference, andmany others. His books have been translated into over12 languages and are used around the world both in industryand college settings.About the Technical EditorJames H. (Jim) Pence is a full-time writer, editor, speaker,singer, and performance chalk artist. Jim broke into bookpublishing in 2001 with How to Do Everything with HTML,a how-to book on Web authoring, written “by a nontechie fornontechies,” and published by McGraw-Hill Professional. Hefollowed this book the same year with another book forMcGraw-Hill: Cascading Style Sheets: A Beginner’s Guide.McGraw-Hill published a second edition of Jim’s HTMLbook, re-titled How to Do Everything with HTML & XHTML,in 2003.Jim is also a published novelist. He is the author of BlindSight (Tyndale, 2003), a suspense/thriller novel set in themind-control cults, and The Angel (Kregel, 2006), set againstthe backdrop of the euthanasia and physician-assisted suicidemovements. Jim moved into “true crime” writing with hislatest book, Terror by Night (Tyndale, 2009). Terror by Night isthe true story of the brutal 2008 murders of the Caffey familyin Emory, Texas. You can learn more about Jim’s books andother creative projects at his Web site: www.jamespence.com.

HTML & CSS:The Complete Reference,Fifth EditionThomas A. PowellNew York Chicago San FranciscoLisbon London Madrid Mexico CityMilan New Delhi San JuanSeoul Singapore Sydney Toronto

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Contents at a GlancePart I Core Markup123Traditional HTML and XHTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Introducing HTML5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HTML and XHTML Element Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . .355133Part II Core Style456Introduction to CSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CSS Syntax and Property Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CSS3 Proprietary and Emerging Features Reference . . . . . . . . . . . . . . . . . .429521613Part III AppendixesABCDECharacter Entities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .URLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Reading a Document Type Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .727751765783801Index809.v

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ContentsAcknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiiiPart I Core Markup1Traditional HTML and XHTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .First Look at HTML and XHTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Hello HTML and XHTML World . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Viewing Markup Locally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Viewing Markup with a Web Server . . . . . . . . . . . . . . . . . . . . . . . . . . .HTML and XHTML: Version History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HTML and XHTML DTDs: The Specifications Up Close . . . . . . . . . . . . . . . .Document Type Statements and Language Versions . . . . . . . . . . . . .(X)HTML Document Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .The Document Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .The Document Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Browsers and (X)HTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .The Doctype Switch and Browser Rendering Modes . . . . . . . . . . . . .The Rules of (X)HTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HTML Is Not Case Sensitive, XHTML Is . . . . . . . . . . . . . . . . . . . . . . .Attribute Values May Be Case Sensitive . . . . . . . . . . . . . . . . . . . . . . . .(X)HTML Is Sensitive to a Single Whitespace Character . . . . . . . . . .(X)HTML Follows a Content Model . . . . . . . . . . . . . . . . . . . . . . . . . . .Elements Should Have Close Tags Unless Empty . . . . . . . . . . . . . . . .Unused Elements May Minimize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Elements Should Nest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Attributes Should Be Quoted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Entities Should Be Used for Special Characters . . . . . . . . . . . . . . . . . .Browsers Ignore Unknown Attributes and Elements . . . . . . . . . . . . .Major Themes of (X)HTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Logical and Physical Markup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Standards vs. Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Myths and Misconceptions About HTML and XHTML . . . . . . . . . . .The Future of Markup—Two Paths? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .XHTML: Web Page Markup XML Style . . . . . . . . . . . . . . . . . . . . . . . .HTML5: Back to the Future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54647494952532Introducing HTML5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Hello HTML5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Loose Syntax Returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .XHTML5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55555860vii