Introduction

# Introduction This book is not an exhaustive reference on DOM scripting or [JavaScript](http://javascriptenlightenment.com/). It may, however, be the most exhaustive book written about DOM scripting without the use of a library/framework. The lack of authorship around this topic is not without good reason. Most technical authors are not willing to wrangle this topic because of the differences that exist among legacy browsers and their implementations of the DOM specifications (or lack thereof). For the purpose of this book (i.e. grokking the concepts), I'm going to sidestep the browser API mess and dying browser discrepancies in an effort to expose the modern DOM. That's right, I'm going to sidestep the ugliness in an effort to focus on the here and now. After all, we have solutions like jQuery to deal with all that browser ugliness, and you should definitely be leveraging something like jQuery when dealing with deprecated browsers. While I am not promoting the idea of only going native when it comes to DOM scripting, I did write this book in part so that developers may realize that DOM libraries are not always required when scripting the DOM. I also wrote for the lucky few who get to write JavaScript code for a single environment (i.e. one browser, mobile browsers, or HTML+CSS+JavaScript-to-native via something like PhoneGap). What you learn in this book may just make a DOM library unnecessary in ideal situations, say for example, some light DOM scripting for deployment on a Webkit mobile browser only. ## Who should read this book As I authored this book, I specifically had two types of developers in mind. I assume both types already have an intermediate to advanced knowledge of JavaScript, HTML, and CSS. The first developer is someone who has a good handle on JavaScript or jQuery, but has really never taken the time to understand the purpose and value of a library like jQuery (the reason for its rhyme, if you will). Equipped with the knowledge from this book, that developer should fully be able to understand the value provided by jQuery for scripting the DOM. And not just the value, but how jQuery abstracts the DOM and where and why jQuery is filling the gaps. The second type of developer is an engineer who is tasked with scripting HTML documents that will only run in modern browsers or that will get ported to native code for multiple OS's and device distributions (e.g. PhoneGap) and needs to avoid the overhead (i.e. size or size v.s. use) of a library. ## Technical intentions, allowances, & limitations * The content and code contained in this book was written with modern (IE9+, Firefox latest, Chrome latest, Safari latest, Opera latest) browsers in mind. It was my goal to only include concepts and code that are native to modern browsers. If I venture outside of this goal I will bring this fact to the readers attention. I've generally steered away from including anything in this book that is browser specific or implemented in a minority of the modern browsers. * I'm not attempting in this book to dogmatically focus on a specific DOM, CSS, or HTML specification. Its not my goal here to dogmatically represent a specific specification. This would be too large of an undertaking (with little value IMO) given the number of specifications at work and the history/status of browsers correctly implementing the specifications. I have leverage and balanced in a very subjective manner the content from several specifications ([Document Object Model (DOM) Level 3 Core Specification](http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/core.html), [DOM4](http://www.w3.org/TR/dom/), [Document Object Model HTML ](http://www.w3.org/TR/2003/REC-DOM-Level-2-HTML-20030109/html.html), [Element Traversal Specification](http://www.w3.org/TR/ElementTraversal/), [Selectors API Level 2](http://www.w3.org/TR/selectors-api2/), [DOM Parsing and Serialization](http://html5.org/specs/dom-parsing.html), [HTML 5 Reference](http://dev.w3.org/html5/html-author/), [HTML 5 - A vocabulary and associated APIs for HTML and XHTML](http://www.w3.org/TR/html5/), [HTML Living Standard](http://www.whatwg.org/specs/web-apps/current-work/multipage/),[HTML 5 - A technical specification for Web Developers](http://developers.whatwg.org/), [DOM Living Standard](http://dom.spec.whatwg.org/)). The content for this book is based more on where the community is and less on dogmatically attempting to express a specific spec. * I'm covering several hand picked topics that are not DOM specific. I've included these topics in this book to help the reader build a proper understanding of the DOM in relationship to CSS and JavaScript. * I've purposely left out any details as it pertains to XML or XHTML. * I've purposely excluded the form and table api's to keep the book small. But I can see these sections being added in the future. ## License The DOM Enlightenment HTML version is released under a [Creative Commons Attribution-Noncommercial-No Derivative Works 3.0](http://creativecommons.org/licenses/by-nc-nd/3.0/) unported license. ## Hard Copy & eBook [O'Reilly](http://oreilly.com/) will release and sell a hard copy & eBook in the near future.