jQuery Cookbook Solutions Examples for jQuery Developers (Animal Guide) (Cody Lindley) (z-library.sk, 1lib.sk, z-lib.sk)

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jQuery Cookbook

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jQuery Cookbook jQuery Community Experts Beijing • Cambridge • Farnham • Köln • Sebastopol • Taipei • Tokyo

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jQuery Cookbook by jQuery Community Experts Copyright © 2010 Cody Lindley. 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 corporate@oreilly.com. Editor: Simon St.Laurent Production Editor: Sarah Schneider Copyeditor: Kim Wimpsett Proofreader: Andrea Fox Production Services: Molly Sharp Indexer: Fred Brown Cover Designer: Karen Montgomery Interior Designer: David Futato Illustrator: Robert Romano Printing History: November 2009: First Edition. O’Reilly and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. jQuery Cookbook, the image of an ermine, 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. TM This book uses RepKover, a durable and flexible lay-flat binding. ISBN: 978-0-596-15977-1 [S] 1257774409

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Table of Contents Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii 1. jQuery Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Including the jQuery Library Code in an HTML Page 9 1.2 Executing jQuery/JavaScript Coded After the DOM Has Loaded but Before Complete Page Load 10 1.3 Selecting DOM Elements Using Selectors and the jQuery Function 13 1.4 Selecting DOM Elements Within a Specified Context 15 1.5 Filtering a Wrapper Set of DOM Elements 16 1.6 Finding Descendant Elements Within the Currently Selected Wrapper Set 18 1.7 Returning to the Prior Selection Before a Destructive Change 19 1.8 Including the Previous Selection with the Current Selection 20 1.9 Traversing the DOM Based on Your Current Context to Acquire a New Set of DOM Elements 21 1.10 Creating, Operating on, and Inserting DOM Elements 23 1.11 Removing DOM Elements 24 1.12 Replacing DOM Elements 26 1.13 Cloning DOM Elements 27 1.14 Getting, Setting, and Removing DOM Element Attributes 29 1.15 Getting and Setting HTML Content 30 1.16 Getting and Setting Text Content 31 1.17 Using the $ Alias Without Creating Global Conflicts 32 2. Selecting Elements with jQuery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2.1 Selecting Child Elements Only 36 2.2 Selecting Specific Siblings 37 v

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2.3 Selecting Elements by Index Order 39 2.4 Selecting Elements That Are Currently Animating 41 2.5 Selecting Elements Based on What They Contain 42 2.6 Selecting Elements by What They Don’t Match 43 2.7 Selecting Elements Based on Their Visibility 43 2.8 Selecting Elements Based on Attributes 44 2.9 Selecting Form Elements by Type 46 2.10 Selecting an Element with Specific Characteristics 47 2.11 Using the Context Parameter 48 2.12 Creating a Custom Filter Selector 50 3. Beyond the Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.1 Looping Through a Set of Selected Results 53 3.2 Reducing the Selection Set to a Specified Item 56 3.3 Convert a Selected jQuery Object into a Raw DOM Object 59 3.4 Getting the Index of an Item in a Selection 62 3.5 Making a Unique Array of Values from an Existing Array 64 3.6 Performing an Action on a Subset of the Selected Set 67 3.7 Configuring jQuery Not to Conflict with Other Libraries 69 3.8 Adding Functionality with Plugins 72 3.9 Determining the Exact Query That Was Used 74 4. jQuery Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 4.1 Detecting Features with jQuery.support 77 4.2 Iterating Over Arrays and Objects with jQuery.each 79 4.3 Filtering Arrays with jQuery.grep 80 4.4 Iterating and Modifying Array Entries with jQuery.map 81 4.5 Combining Two Arrays with jQuery.merge 81 4.6 Filtering Out Duplicate Array Entries with jQuery.unique 82 4.7 Testing Callback Functions with jQuery.isFunction 82 4.8 Removing Whitespace from Strings or Form Values with jQuery.trim 83 4.9 Attaching Objects and Data to DOM with jQuery.data 84 4.10 Extending Objects with jQuery.extend 85 5. Faster, Simpler, More Fun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 5.1 That’s Not jQuery, It’s JavaScript! 87 5.2 What’s Wrong with $(this)? 88 5.3 Removing Redundant Repetition 91 5.4 Formatting Your jQuery Chains 92 5.5 Borrowing Code from Other Libraries 94 5.6 Writing a Custom Iterator 96 5.7 Toggling an Attribute 99 vi | Table of Contents

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5.8 Finding the Bottlenecks 101 5.9 Caching Your jQuery Objects 105 5.10 Writing Faster Selectors 107 5.11 Loading Tables Faster 109 5.12 Coding Bare-Metal Loops 112 5.13 Reducing Name Lookups 115 5.14 Updating the DOM Faster with .innerHTML 117 5.15 Debugging? Break Those Chains 118 5.16 Is It a jQuery Bug? 120 5.17 Tracing into jQuery 121 5.18 Making Fewer Server Requests 123 5.19 Writing Unobtrusive JavaScript 126 5.20 Using jQuery for Progressive Enhancement 128 5.21 Making Your Pages Accessible 130 6. Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 6.1 Finding the Dimensions of the Window and Document 135 6.2 Finding the Dimensions of an Element 137 6.3 Finding the Offset of an Element 139 6.4 Scrolling an Element into View 141 6.5 Determining Whether an Element Is Within the Viewport 143 6.6 Centering an Element Within the Viewport 146 6.7 Absolutely Positioning an Element at Its Current Position 147 6.8 Positioning an Element Relative to Another Element 147 6.9 Switching Stylesheets Based on Browser Width 148 7. Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 7.1 Sliding and Fading Elements in and out of View 153 7.2 Making Elements Visible by Sliding Them Up 156 7.3 Creating a Horizontal Accordion 157 7.4 Simultaneously Sliding and Fading Elements 161 7.5 Applying Sequential Effects 162 7.6 Determining Whether Elements Are Currently Being Animated 164 7.7 Stopping and Resetting Animations 165 7.8 Using Custom Easing Methods for Effects 166 7.9 Disabling All Effects 168 7.10 Using jQuery UI for Advanced Effects 168 8. Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 8.1 Attaching a Handler to Many Events 172 8.2 Reusing a Handler Function with Different Data 173 8.3 Removing a Whole Set of Event Handlers 175 8.4 Triggering Specific Event Handlers 176 Table of Contents | vii

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8.5 Passing Dynamic Data to Event Handlers 177 8.6 Accessing an Element ASAP (Before document.ready) 179 8.7 Stopping the Handler Execution Loop 182 8.8 Getting the Correct Element When Using event.target 184 8.9 Avoid Multiple hover() Animations in Parallel 185 8.10 Making Event Handlers Work for Newly Added Elements 187 9. Advanced Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 9.1 Getting jQuery to Work When Loaded Dynamically 191 9.2 Speeding Up Global Event Triggering 192 9.3 Creating Your Own Events 195 9.4 Letting Event Handlers Provide Needed Data 198 9.5 Creating Event-Driven Plugins 201 9.6 Getting Notified When jQuery Methods Are Called 205 9.7 Using Objects’ Methods as Event Listeners 208 10. HTML Form Enhancements from Scratch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 10.1 Focusing a Text Input on Page Load 212 10.2 Disabling and Enabling Form Elements 213 10.3 Selecting Radio Buttons Automatically 216 10.4 (De)selecting All Checkboxes Using Dedicated Links 218 10.5 (De)selecting All Checkboxes Using a Single Toggle 219 10.6 Adding and Removing Select Options 221 10.7 Autotabbing Based on Character Count 222 10.8 Displaying Remaining Character Count 224 10.9 Constraining Text Input to Specific Characters 226 10.10 Submitting a Form Using Ajax 228 10.11 Validating Forms 229 11. HTML Form Enhancements with Plugins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 11.1 Validating Forms 238 11.2 Creating Masked Input Fields 247 11.3 Autocompleting Text Fields 249 11.4 Selecting a Range of Values 250 11.5 Entering a Range-Constrained Value 253 11.6 Uploading Files in the Background 255 11.7 Limiting the Length of Text Inputs 256 11.8 Displaying Labels Above Input Fields 257 11.9 Growing an Input with Its Content 259 11.10 Choosing a Date 260 12. jQuery Plugins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 12.1 Where Do You Find jQuery Plugins? 263 viii | Table of Contents

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12.2 When Should You Write a jQuery Plugin? 265 12.3 Writing Your First jQuery Plugin 267 12.4 Passing Options into Your Plugin 268 12.5 Using the $ Shortcut in Your Plugin 270 12.6 Including Private Functions in Your Plugin 272 12.7 Supporting the Metadata Plugin 273 12.8 Adding a Static Function to Your Plugin 275 12.9 Unit Testing Your Plugin with QUnit 277 13. Interface Components from Scratch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279 13.1 Creating Custom Tool Tips 280 13.2 Navigating with a File-Tree Expander 285 13.3 Expanding an Accordion 288 13.4 Tabbing Through a Document 293 13.5 Displaying a Simple Modal Window 296 13.6 Building Drop-Down Menus 303 13.7 Cross-Fading Rotating Images 305 13.8 Sliding Panels 310 14. User Interfaces with jQuery UI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315 14.1 Including the Entire jQuery UI Suite 317 14.2 Including an Individual jQuery UI Plugin or Two 318 14.3 Initializing a jQuery UI Plugin with Default Options 319 14.4 Initializing a jQuery UI Plugin with Custom Options 320 14.5 Creating Your Very Own jQuery UI Plugin Defaults 321 14.6 Getting and Setting jQuery UI Plugin Options 323 14.7 Calling jQuery UI Plugin Methods 323 14.8 Handling jQuery UI Plugin Events 324 14.9 Destroying a jQuery UI Plugin 326 14.10 Creating a jQuery UI Music Player 327 15. jQuery UI Theming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341 15.1 Styling jQuery UI Widgets with ThemeRoller 345 15.2 Overriding jQuery UI Layout and Theme Styles 360 15.3 Applying a Theme to Non-jQuery UI Components 370 15.4 Referencing Multiple Themes on a Single Page 379 15.5 Appendix: Additional CSS Resources 388 16. jQuery, Ajax, Data Formats: HTML, XML, JSON, JSONP . . . . . . . . . . . . . . . . . . . . . . . 391 16.1 jQuery and Ajax 391 16.2 Using Ajax on Your Whole Site 394 16.3 Using Simple Ajax with User Feedback 396 16.4 Using Ajax Shortcuts and Data Types 400 Table of Contents | ix

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16.5 Using HTML Fragments and jQuery 403 16.6 Converting XML to DOM 404 16.7 Creating JSON 405 16.8 Parsing JSON 406 16.9 Using jQuery and JSONP 407 17. Using jQuery in Large Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411 17.1 Using Client-Side Storage 411 17.2 Saving Application State for a Single Session 414 17.3 Saving Application State Between Sessions 416 17.4 Using a JavaScript Template Engine 417 17.5 Queuing Ajax Requests 420 17.6 Dealing with Ajax and the Back Button 422 17.7 Putting JavaScript at the End of a Page 423 18. Unit Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425 18.1 Automating Unit Testing 425 18.2 Asserting Results 427 18.3 Testing Synchronous Callbacks 429 18.4 Testing Asynchronous Callbacks 429 18.5 Testing User Actions 431 18.6 Keeping Tests Atomic 432 18.7 Grouping Tests 433 18.8 Selecting Tests to Run 434 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437 x | Table of Contents

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Foreword When I first started work on building jQuery, back in 2005, I had a simple goal in mind: I wanted to be able to write a web application and have it work in all the major browsers—without further tinkering and bug fixing. It was a couple of months before I had a set of utilities that were stable enough to achieve that goal for my personal use. I thought I was relatively done at this point; little did I know that my work was just beginning. Since those simple beginnings, jQuery has grown and adapted as new users use the library for their projects. This has proven to be the most challenging part of developing a JavaScript library; while it is quite easy to build a library that’ll work for yourself or a specific application, it becomes incredibly challenging to develop a library that’ll work in as many environments as possible (old browsers, legacy web pages, and strange markup abound). Surprisingly, even as jQuery has adapted to handle more use cases, most of the original API has stayed intact. One thing I find particularly interesting is to see how developers use jQuery and make it their own. As someone with a background in computer science, I find it quite sur- prising that so many designers and nonprogrammers find jQuery to be compelling. Seeing how they interact with the library has given me a better appreciation of simple API design. Additionally, seeing many advanced programmers take jQuery and develop large, complex applications with it has been quite illuminating. The best part of all of this, though, is the ability to learn from everyone who uses the library. A side benefit of using jQuery is its extensible plugin structure. When I first developed jQuery, I was sure to include some simple ways for developers to extend the API that it provided. This has blossomed into a large and varied community of plugins, encom- passing a whole ecosystem of applications, developers, and use cases. Much of jQuery’s growth has been fueled by this community—without it, the library wouldn’t be where it is today, so I’m glad that there are chapters dedicated to some of the most interesting plugins and what you can do with them. One of the best ways to expand your precon- ceived notion of what you can do with jQuery is to learn and use code from the jQuery plugin community. xi

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This is largely what makes something like a cookbook so interesting: it takes the cool things that developers have done, and have learned, in their day-to-day coding and distills it to bite-sized chunks for later consumption. Personally, I find a cookbook to be one of the best ways to challenge my preconceived notions of a language or library. I love seeing cases where an API that I thought I knew well is turned around and used in new and interesting ways. I hope this book is able to serve you well, teaching you new and interesting ways to use jQuery. —John Resig Creator, Lead Developer, jQuery xii | Foreword

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Contributors Chapter Authors Jonathan Sharp has been passionate about the Internet and web development since 1996. Over the years that have followed, he has worked for startups and for Fortune 500 corporations. Jonathan founded Out West Media, LLC, in greater Omaha, Ne- braska, and provides frontend engineering and architecture services with a focus on custom XHTML, CSS, and jQuery development. Jonathan is a jQuery core team mem- ber and an author and presenter when not coding. Jonathan is most grateful for his wife, Erin; daughter, Noel; two dogs, and two horses. Rob Burns develops interactive web applications at A Mountain Top, LLC. For the past 12 years he has been exploring website development using a wide range of tools and technologies. In his spare time, he enjoys natural-language processing and the wealth of opportunity in open source software projects. Rebecca Murphey is an independent frontend architecture consultant, crafting cus- tom frontend solutions that serve as the glue between server and browser. She also provides training in frontend development, with an emphasis on the jQuery library. She lives with her partner, two dogs, and two cats in Durham, North Carolina. Ariel Flesler is a web developer and a video game programmer. He’s been contributing to jQuery since January 2007 and joined the core team in May 2008. He is 23 years old and was born in Buenos Aires, Argentina. He’s studying at the National Technological University (Argentina) and is hoping to become a systems analyst by 2010 and a systems engineer by 2012. He started working as an ASP.NET(C#) programmer and then switched to client-side development of XHTML sites and Ajax applications. He’s cur- rently working at QB9 where he develops AS3-based casual games and MMOs. Cody Lindley is a Christian, husband, son, father, brother, outdoor enthusiast, and professional client-side engineer. Since 1997 he has been passionate about HTML, CSS, JavaScript, Flash, interaction design, interface design, and HCI. He is most well known in the jQuery community for the creation of ThickBox, a modal/dialog solution. In 2008 he officially joined the jQuery team as an evangelist. His current focus has been xiii

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on client-side optimization techniques as well as speaking and writing about jQuery. His website is http://www.codylindley.com. Remy Sharp is a developer, author, speaker, and blogger. Remy started his professional web development career in 1999 as the sole developer for a finance website and, as such, was exposed to all aspects of running the website during, and long after, the dotcom boom. Today he runs his own development company called Left Logic in Brighton, UK, writing and coding JavaScript, jQuery, HTML 5, CSS, PHP, Perl, and anything else he can get his hands on. Mike Hostetler is an inventor, entrepreneur, programmer, and proud father. Having worked with web technologies since the mid-1990s, Mike has had extensive experience developing web applications with PHP and JavaScript. Currently, Mike works at the helm of A Mountain Top, LLC, a web technology consulting firm in Denver, Colorado. Heavily involved in open source, Mike is a member of the jQuery core team, leads the QCubed PHP5 Framework project, and participates in the Drupal project. When not in front of a computer, Mike enjoys hiking, fly fishing, snowboarding, and spending time with his family. Ralph Whitbeck is a graduate of the Rochester Institute of Technology and is currently a senior developer for BrandLogic Corporation in Rochester, New York. His respon- sibilities at BrandLogic include interface design, usability testing, and web and appli- cation development. Ralph is able to program complex web application systems in ASP.NET, C#, and SQL Server and also uses client-side technologies such as XHTML, CSS, and JavaScript/jQuery in order to implement client-approved designs. Ralph of- ficially joined the jQuery team as an evangelist in October 2009. Ralph enjoys spending time with his wife, Hope, and his three boys, Brandon, Jordan, and Ralphie. You can find out more about Ralph on his personal blog. Nathan Smith is a goofy guy who has been building websites since late last century. He enjoys hand-coding HTML, CSS, and JavaScript. He also dabbles in design and information architecture. He has written for online and paper publications such as Adobe Developer Center, Digital Web, and .NET Magazine. He has spoken at venues including Adobe MAX, BibleTech, Drupal Camp, Echo Conference, Ministry 2.0, Re- fresh Dallas, and Webmaster Jam Session. Nathan works as a UX developer at Fellow- shipTech.com. He holds a Master of Divinity degree from Asbury Theological Semi- nary. He started Godbit.com, a community resource aimed at helping churches and ministries make better use of the Web. He also created the 960 Grid System, a frame- work for sketching, designing, and coding page layouts. Brian Cherne is a software developer with more than a decade of experience blue- printing and building web-based applications, kiosks, and high-traffic e-commerce websites. He is also the author of the hoverIntent jQuery plugin. When not geeking out with code, Brian can be found ballroom dancing, practicing martial arts, or studying Russian culture and language. xiv | Contributors

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Jörn Zaefferer is a professional software developer from Cologne, Germany. He cre- ates application programming interfaces (APIs), graphical user interfaces (GUIs), soft- ware architectures, and databases, for both web and desktop applications. His work focuses on the Java platform, while his client-side scripting revolves around jQuery. He started contributing to jQuery in mid-2006 and has since cocreated and maintained QUnit, jQuery’s unit testing framework; released and maintained a half dozen very popular jQuery plugins; and contributed to jQuery books as both author and tech reviewer. He is also a lead developer for jQuery UI. James Padolsey is an enthusiastic web developer and blogger based in London, UK. He’s been crazy about jQuery since he first discovered it; he’s written tutorials teaching it, articles and blog posts discussing it, and plenty of plugins for the community. James’ plans for the future include a computer science degree from the University of Kent and a career that allows him to continually push boundaries. His website is http://james .padolsey.com. Scott González is a web application developer living in Raleigh, North Carolina, who enjoys building highly dynamic systems and flexible, scalable frameworks. He has been contributing to jQuery since 2007 and is currently the development lead for jQuery UI, jQuery’s official user interface library. Scott also writes tutorials about jQuery and jQuery UI on nemikor.com and speaks about jQuery at conferences. Michael Geary started developing software when editing code meant punching a paper tape on a Teletype machine, and “standards-compliant” meant following ECMA-10 Standard for Data Interchange on Punched Tape. Today Mike is a web and Android developer with a particular interest in writing fast, clean, and simple code, and he enjoys helping other developers on the jQuery mailing lists. Mike’s recent projects include a series of 2008 election result and voter information maps for Google; and StrataLogic, a mashup of traditional classroom wall maps and atlases overlaid on Google Earth. His website is http://mg.to. Maggie Wachs, Scott Jehl, Todd Parker, and Patty Toland are Filament Group. Together, they design and develop highly functional user interfaces for consumer- and business-oriented websites, wireless devices, and installed and web-based applications, with a specific focus on delivering intuitive and usable experiences that are also broadly accessible. They are sponsor and design leads of the jQuery UI team, for whom they designed and developed ThemeRoller.com, and they actively contribute to ongoing development of the official jQuery UI library and CSS Framework. Richard D. Worth is a web UI developer. He is the release manager for jQuery UI and one of its longest-contributing developers. He is author or coauthor of the Dialog, Progressbar, Selectable, and Slider plugins. Richard also enjoys speaking and consulting on jQuery and jQuery UI around the world. Richard is raising a growing family in Northern Virginia (Washington, D.C. suburbs) with his lovely wife, Nancy. They have been blessed to date with three beautiful children: Naomi, Asher, and Isaiah. Richard’s website is http://rdworth.org/. Contributors | xv

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Tech Editors Karl Swedberg, after having taught high school English, edited copy for an advertising agency, and owned a coffee house, began his career as a web developer four years ago. He now works for Fusionary Media in Grand Rapids, Michigan, where he specializes in client-side scripting and interaction design. Karl is a member of the jQuery project team and coauthor of Learning jQuery 1.3 and jQuery Reference Guide (both published by Packt). You can find some of his tips and tutorials at http://www.learningjquery.com. Dave Methvin is the chief technology officer at PCPitstop.com and one of the founding partners of the company. He has been using jQuery since 2006, is active on the jQuery help groups, and has contributed several popular jQuery plugins including Corner and Splitter. Before joining PC Pitstop, Dave served as executive editor at both PC Tech Journal and Windows Magazine, where he wrote a column on JavaScript. He continues to write for several PC-related websites including InformationWeek. Dave holds bach- elor’s and master’s degrees in computer science from the University of Virginia. David Serduke is a frontend programmer who is recently spending much of his time server side. After programming for many years, he started using jQuery in late 2007 and shortly after joined the jQuery core team. David is currently creating websites for financial institutions and bringing the benefits of jQuery to ASP.NET enterprise ap- plications. David lives in northern California where he received a bachelor’s degree from the University of California at Berkeley in electrical engineering and an MBA from St. Mary’s College. Scott Mark is an enterprise application architect at Medtronic. He works on web-based personalized information portals and transactional applications with an eye toward maintaining high usability in a regulated environment. His key interest areas at the moment are rich Internet applications and multitouch user interface technologies. Scott lives in Minnesota with his lovely wife, two sons, and a black lab. He blogs about technology at http://scottmark.wordpress.com and long-distance trail running at http:// runlikemonkey.com. xvi | Contributors

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Preface The jQuery library has taken the frontend development world by storm. Its dead-simple syntax makes once-complicated tasks downright trivial—enjoyable, even. Many a de- veloper has been quickly seduced by its elegance and clarity. If you’ve started using the library, you’re already adding rich, interactive experiences to your projects. Getting started is easy, but as is the case with many of the tools we use to develop websites, it can take months or even years to fully appreciate the breadth and depth of the jQuery library. The library is chock-full of features you might never have known to wish for. Once you know about them, they can dramatically change how you approach the problems you’re called upon to solve. The goal of this cookbook is to expose you, dear reader, to the patterns and practices of some of the leading frontend developers who use jQuery in their everyday projects. Over the course of 18 chapters, they’ll guide you through solutions to problems that range from straightforward to complex. Whether you’re a jQuery newcomer or a griz- zled JavaScript veteran, you’re likely to gain new insight into harnessing the full power of jQuery to create compelling, robust, high-performance user interfaces. Who This Book Is For Maybe you’re a designer who is intrigued by the interactivity that jQuery can provide. Maybe you’re a frontend developer who has worked with jQuery before and wants to see how other people accomplish common tasks. Maybe you’re a server-side developer who’s frequently called upon to write client-side code. Truth be told, this cookbook will be valuable to anyone who works with jQuery—or who hopes to work with jQuery. If you’re just starting out with the library, you may want to consider pairing this book with Learning jQuery 1.3 from Packt, or jQuery in Action from Manning. If you’re already using jQuery in your projects, this book will serve to enhance your knowledge of the library’s features, hidden gems, and idiosyncrasies. xvii

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What You’ll Learn We’ll start out by covering the basics and general best practices—including jQuery in your page, making selections, and traversing and manipulation. Even frequent jQuery users are likely to pick up a tip or two. From there, we move on to real-world use cases, walking you through tried-and-true (and tested) solutions to frequent problems involving events, effects, dimensions, forms, and user interface elements (with and without the help of jQuery UI). At the end, we’ll take a look at testing your jQuery applications and integrating jQuery into complex sites. Along the way, you’ll learn strategies for leveraging jQuery to solve problems that go far beyond the basics. We’ll explore how to make the most of jQuery’s event manage- ment system, including custom events and custom event data; how to progressively enhance forms; how to position and reposition elements on the page; how to create user interface elements such as tabs, accordions, and modals from scratch; how to craft your code for readability and maintainability; how to optimize your code to ease testing, eliminate bottlenecks, and ensure peak performance; and more. Because this is a cookbook and not a manual, you’re of course welcome to cherry-pick the recipes you read; the individual recipes alone are worth the price of admission. As a whole, though, the book provides a rare glimpse into the problem-solving approaches of some of the best and brightest in the jQuery community. With that in mind, we encourage you to at least skim it from front to back—you never know which line of code will provide the “Aha!” moment you need to take your skills to the next level. jQuery Style and Conventions jQuery places a heavy emphasis on chaining—calling methods on element selections in sequence, confident in the knowledge that each method will give you back a selection of elements you can continue to work with. This pattern is explained in depth in Chapter 1—if you’re new to the library, you’ll want to understand this concept, because it is used heavily in subsequent chapters. jQuery’s features are organized into a handful of simple categories: core functionality, selecting, manipulating, traversing, CSS, attributes, events, effects, Ajax, and utilities. Learning these categories, and how methods fit into them, will greatly enhance your understanding of the material in this book. One of the best practices this book will cover is the concept of storing element selections in a variable, rather than making the same selection repeatedly. When a selection is stored in a variable, it is commonplace for that variable to begin with the $ character, indicating that it is a jQuery object. This can make code easier to read and maintain, but it should be understood that starting the variable name with the $ character is merely a convention; it carries no special meaning, unlike in other languages such as PHP. xviii | Preface