This book covers the JavaScript language and the JavaScript APIs implemented by web browsers and by Node. I wrote it for readers with some prior programming experience who want to learn JavaScript and also for programmers who already use JavaScript but want to take their understanding to a new level and really master the language. My goal with this book is to document the JavaScript language comprehensively and definitively and to provide an in-depth introduction to the most important client-side and server-side APIs available to JavaScript programs. As a result, this is a long and detailed book. My hope, however, is that it will reward careful study and that the time you spend reading it will be easily recouped in the form of higher programming productivity.
Previous editions of this book included a comprehensive reference section. I no longer feel that it makes sense to include that material in printed form when it is so quick and easy to find up-to-date reference material online. If you need to look up anything related to core or client-side JavaScript, I recommend you visit the MDN website. And for server-side Node APIs, I recommend you go directly to the source and consult the Node.js reference documentation.
I use the following typographical conventions in this book:
Is used for emphasis and to indicate the first use of a term. Italic is also used for email addresses, URLs, and file names.
Constant widthIs used in all JavaScript code and CSS and HTML listings, and generally for anything that you would type literally when programming.
Constant width italicIs occasionally used when explaining JavaScript syntax.
Constant width boldShows commands or other text that should be typed literally by the user
This element signifies a general note.
This element indicates a warning or caution.
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Many people have helped with the creation of this book. I’d like to thank my editor, Angela Rufino, for keeping me on track and for her patience with my missed deadlines. Thanks also to my technical reviewers: Brian Sletten, Elisabeth Robson, Ethan Flanagan, Maximiliano Firtman, Sarah Wachs, and Schalk Neethling. Their comments and suggestions have made this a better book.
The production team at O’Reilly has done their usual fine job: Kristen Brown managed the production process, Deborah Baker was the production editor, Rebecca Demarest drew the figures, and Judy McConville created the index.
Editors, reviewers, and contributors to previous editions of this book have included: Andrew Schulman, Angelo Sirigos, Aristotle Pagaltzis, Brendan Eich, Christian Heilmann, Dan Shafer, Dave C. Mitchell, Deb Cameron, Douglas Crockford, Dr. Tankred Hirschmann, Dylan Schiemann, Frank Willison, Geoff Stearns, Herman Venter, Jay Hodges, Jeff Yates, Joseph Kesselman, Ken Cooper, Larry Sullivan, Lynn Rollins, Neil Berkman, Mike Loukides, Nick Thompson, Norris Boyd, Paula Ferguson, Peter-Paul Koch, Philippe Le Hegaret, Raffaele Cecco, Richard Yaker, Sanders Kleinfeld, Scott Furman, Scott Isaacs, Shon Katzenberger, Terry Allen, Todd Ditchendorf, Vidur Apparao, Waldemar Horwat, and Zachary Kessin.
Writing this seventh edition kept me away from my family for many late nights. My love to them and my thanks for putting up with my absences.