,praise.1687 Page i Monday, February 8, 2010 12:03 PM Praise forHTML & CSS: The Good Parts “Ben has an encyclopedic knowledge of web development and makes even the most obtuse-sounding concepts seem eminently approachable. All while writing a book filled with charm, wit, and aplomb. (Yeah, I hate him, too. Great book, though.)” —EthanMarcotte,coauthorofDesigningwithWebStandards, Third Edition “HTML & CSS: The Good Parts is essential for those who work building web pages and need to take their understanding and knowledge to the next level. Web developers and designers of all types need to have solid depth of understanding of how HTML and CSS workaswellashowtheyinteractwiththebrowser.ThedifferenceIfindbetweenanokay webdesigneranddeveloper(includingthosewhoworkwithtoolsthatcreateandmanage sites)andareallygoodoneisthedepthofunderstandingtheyhaveanduseofHTMLand CSS. This book provides that depth and understanding. “In my opinion one of the best pieces for me in this book is the inclusion of the proper structuring of pages, sites, and the depth of the discussion for integration is essential for the maintenance, use,and even SEO considerations.This is something that far too often gets missed and is not understood well. Having this knowledge and these skills in your toolbeltwillonlyleadtomuchimprovedoutcomesthatareeasiertobuildout,manage, and use.” —Thomas Vander Wal, founder and senior consultant at InfoCloud Solutions “I’vealwayssaidthatthebeauty(andthefrustration)inCSSisthattherearesomanyways todothings.Benhasdoneafantasticjobofhominginonthegood,thebad,andtheugly in the broad CSS realm. His useful real-world approach not only gives you a great refer- ence to the most commonly used elements, properties, and values, but it also addresses the advantages (and pitfalls) of various techniques. Whether you’re working on small or largesites,Benclearlypresentstheprinciplesyouneedtocrankyourskillsuptothenext level.” —Stephanie Sullivan, author,Mastering CSS with Dreamweaver CS4 ,praise.1687 Page ii Monday, February 8, 2010 12:03 PM HTML & CSS: The Good Parts Ben Henick Beijing • Cambridge • Farnham • Köln • Sebastopol • Taipei • Tokyo HTML & CSS: The Good Parts by Ben Henick Copyright © 2010 Ben Henick. All rights reserved. Printed in the United States of America. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (http://my.safaribooksonline.com). For more information, contact our corporate/institutional sales department: 800-998-9938 or [email protected]. Editor: Simon St.Laurent Indexer: Lucie Haskins Production Editor: Loranah Dimant Cover Designer: Karen Montgomery Copyeditor: Emily Quill Interior Designer: David Futato Proofreader: Sada Preisch Illustrator: Robert Romano Printing History: February 2010: First Edition. Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. HTML & CSS: The Good Parts, the image of a ring-tailed cat, and related trade dress are trademarks of O’Reilly Media, Inc. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and O’Reilly Media, Inc., was aware of a trademark claim, the designations have been printed in caps or initial caps. While every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions, or for damages resulting from the use of the information con- tained herein. ISBN: 978-0-596-15760-9 [SB] 1266416276 To the memory of my mother and the patience of my father—each a wellspring of love, hope, and knowledge. Table of Contents Preface .................................................................... xvii 1. Hypertext at the Core .................................................... 1 The Web Without Links 1 URIs 2 Managing Links 3 Improving the User Experience with Linking 3 Hypertext Implementation Challenges 4 2. Working with HTML Markup .............................................. 7 HTML Syntax 7 Tags, Elements, and Attributes 8 Page Structure 10 Rendering Modes, Flavors of HTML, and Document Type Declarations 10 HTML or XHTML? 11 Strict, Transitional, or Frameset? 12 A Tale of Two Box Models 12 Choosing the Right Document Type for Your Project 13 Beautiful Parts: Universal Attributes 14 Providing Stylesheet Hooks with class and id 14 Describing Content with title and lang 15 The contenteditable Attribute in HTML5 17 Separating Content, Structure, Presentation, and Behavior 18 Making Your Sites “Safe As Houses” 18 Separation in Practice 18 Working with Document Trees 19 Browsers, Parsing, and Rendering 20 Dynamic HTML, Ajax, and Rendering 21 3. CSS Overview .......................................................... 23 Connecting Stylesheets to HTML Documents 23 vii Referencing a Stylesheet with link 23 Targeting Internet Explorer Versions with Conditional Comments 24 Replacing link with style 25 Using @import 25 Beware of style Attributes! 25 Targeting Rules to Specific Media 26 Choosing the Elements You Want to Style: Writing Selectors 27 Parents, Children, and Siblings: Element/Node Relationships 28 Simple Selectors 29 Multiple and Descendant Selectors 29 Selecting Direct Child Elements 30 Rule Conflicts, Priority, and Precedence 31 Selector Priority 31 Avoiding Rule Conflicts 32 Value Inheritance 33 CSS Property and Value Survey 33 CSS Units 33 Cross-Media Length and Size Units 34 Pitch and the Value of a Pixel 34 Print-Friendly Length Units 36 font-size Keywords 36 Color Units 37 Key CSS Layout Properties 37 4. Developing a Healthy Relationship with Standards .......................... 41 The Broad Landscape of Web-Related Standards 41 Why Web Standards? 42 Interoperability 42 Market Forces 43 Forward Compatibility 43 Accessibility 43 Vendor Priorities 44 Legacy Asset Inertia 44 Best Practices (and Lack Thereof) 44 Strict Constructionism 45 Taking the Middle Road: Standards-Friendliness 45 Benefits of Standards-Friendliness 46 Rules of Standards-Friendly Development 46 5. Effective Style and Structure ............................................. 49 The Four Habits of Effective Stylists 49 Habit #1: Keeping It Simple 50 Habit #2: Keeping It Flexible 52 viii | Table of Contents