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introduction.html
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<!DOCTYPE html>
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<title>Five Things You Should Know About HTML5 - Dive Into HTML5</title>
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<link rel=stylesheet href=screen.css>
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h1:before{content:"Introduction:"}
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<link rel=prefetch href=past.html>
<p>You are here: <a href=index.html>Home</a> <span class=u>‣</span> <a href=table-of-contents.html#introduction>Dive Into <abbr>HTML5</abbr></a> <span class=u>‣</span>
<h1><br>Five Things You Should Know About HTML5</h1>
<p id=toc>
<p class=a>❧
<h2 id=one>1. It’s not one big thing</h2>
<p style="float:right;margin:0 0 1.75em 1.75em"><img src=i/video.png alt="[mock video player]" width=226 height=166>
<p>You may well ask: “How can I start using <abbr>HTML5</abbr> if older browsers don’t support it?” But the question itself is misleading. <abbr>HTML5</abbr> is not one big thing; it is a collection of individual features. So you can’t detect “<abbr>HTML5</abbr> support,” because that doesn’t make any sense. But you <em>can</em> detect support for individual features, like canvas, video, or geolocation.
<p>You may think of <abbr>HTML</abbr> as tags and angle brackets. That’s an important part of it, but it’s not the whole story. The <abbr>HTML5</abbr> specification also defines how those angle brackets interact with JavaScript, through the Document Object Model (<abbr>DOM</abbr>). <abbr>HTML5</abbr> doesn’t just define a <code><video></code> tag; there is also a corresponding <abbr>DOM</abbr> <abbr>API</abbr> for video objects in the <abbr>DOM</abbr>. You can use this <abbr>API</abbr> to detect support for different video formats, play a video, pause, mute audio, track how much of the video has been downloaded, and everything else you need to build a rich user experience around the <code><video></code> tag itself.
<p><a href=detect.html>Chapter 2</a> and <a href=everything.html>Appendix A</a> will teach you how to properly detect support for each new <abbr>HTML5</abbr> feature.
<h2 id=two>2. You don’t need to throw anything away</h2>
<p style="float:left;margin:0 1.75em 1.75em 0"><img src=i/forms.png alt="[sample form controls]" width=134 height=196>
<p>Love it or hate it, you can’t deny that <abbr>HTML</abbr> 4 is the most successful markup format ever. <abbr>HTML5</abbr> builds on that success. You don’t need to throw away your existing markup. You don’t need to relearn things you already know. If your web application worked yesterday in <abbr>HTML</abbr> 4, it will still work today in <abbr>HTML5</abbr>. Period.
<p>Now, if you want to <em>improve</em> your web applications, you’ve come to the right place. Here’s a concrete example: <abbr>HTML5</abbr> supports all the form controls from <abbr>HTML</abbr> 4, but it also includes new input controls. Some of these are long-overdue additions like sliders and date pickers; others are more subtle. For example, the <code>email</code> input type looks just like a text box, but mobile browsers will customize their onscreen keyboard to make it easier to type email addresses. Older browsers that don’t support the <code>email</code> input type will treat it as a regular text field, and the form still works with no markup changes or scripting hacks. This means you can start improving your web forms <em>today</em>, even if some of your visitors are stuck on IE 6.
<p>Read all the gory details about <abbr>HTML5</abbr> forms in <a href=forms.html>Chapter 9</a>.
<h2 id=three>3. It’s easy to get started</h2>
<p style="float:right;margin:0 0 1.75em 1.75em"><img src=i/markup-with-arrow.png alt="[sample HTML markup]" width=234 height=202>
<p>“Upgrading” to <abbr>HTML5</abbr> can be as simple as changing your <i>doctype</i>. The doctype should already be on the first line of every <abbr>HTML</abbr> page. Previous versions of <abbr>HTML</abbr> defined a lot of doctypes, and choosing the right one could be tricky. In <abbr>HTML5</abbr>, there is only one doctype:
<blockquote>
<p><code><!DOCTYPE html></code>
</blockquote>
<p>Upgrading to the <abbr>HTML5</abbr> doctype won’t break your existing markup, because all the tags defined in HTML 4 are still supported in <abbr>HTML5</abbr>. But it will allow you to use — and validate — new semantic elements like <code><article></code>, <code><section></code>, <code><header></code>, and <code><footer></code>. You’ll learn all about these new elements in <a href=semantics.html>Chapter 3</a>.
<h2 id=four>4. It already works</h2>
<p style="float:left;margin:0 1.75em 1.75em 0"><img src=i/rel-email.png alt="[form field with onscreen keyboard]" width=227 height=192>
<p>Whether you want to draw on a canvas, play video, design better forms, or build web applications that work offline, you’ll find that <abbr>HTML5</abbr> is already well-supported. Firefox, Safari, Chrome, Opera, and mobile browsers already support canvas (<a href=canvas.html>Chapter 4</a>), video (<a href=video.html>Chapter 5</a>), geolocation (<a href=geolocation.html>Chapter 6</a>), local storage (<a href=storage.html>Chapter 7</a>), and more. Google already supports microdata annotations (<a href=extensibility.html>Chapter 10</a>). Even Microsoft — rarely known for blazing the trail of standards support — supports most <abbr>HTML5</abbr> features in Internet Explorer 9.
<p style="float:right;margin:0 0 1.75em 1.75em"><img src=i/gears.png alt="[Gears saying "I can help"]" width=125 height=75>
<p>Each chapter of this book includes the all-too-familiar browser compatibility charts. But more importantly, each chapter includes a frank discussion of your options if you need to support older browsers. <abbr>HTML5</abbr> features like geolocation (<a href=geolocation.html>Chapter 6</a>) and video (<a href=video.html>Chapter 5</a>) were first provided by browser plugins like Gears or Flash. Other features, like canvas (<a href=canvas.html>Chapter 4</a>), can be emulated entirely in JavaScript. This book will teach you how to target the native features of modern browsers, without leaving older browsers behind.
<h2 id=five>5. It’s here to stay</h2>
<p>Tim Berners-Lee invented the world wide web in the early 1990s. He later founded the <abbr>W3C</abbr> to act as a steward of web standards, which the organization has done for more than 15 years. Here is what the <abbr>W3C</abbr> had to say about the future of web standards, in July 2009:
<blockquote cite=http://www.w3.org/News/2009#item119>
<p>Today the Director announces that when the <abbr>XHTML</abbr> 2 Working Group charter expires as scheduled at the end of 2009, the charter will not be renewed. By doing so, and by increasing resources in the <abbr>HTML</abbr> Working Group, <abbr>W3C</abbr> hopes to accelerate the progress of <abbr>HTML5</abbr> and clarify <abbr>W3C</abbr>’s position regarding the future of <abbr>HTML</abbr>.
</blockquote>
<p><abbr>HTML5</abbr> is here to stay. <a href=past.html>Let’s dive in</a>.
<p class=a>❧
<div class=pf>
<h4>Did You Know?</h4>
<div class=moneybags>
<blockquote><p>In association with Google Press, O’Reilly is distributing this book in a variety of formats, including paper, ePub, Mobi, and <abbr>DRM</abbr>-free <abbr>PDF</abbr>. The paid edition is called “HTML5: Up & Running,” and it is available now.
<p>If you liked this introduction and want to show your appreciation, you can <a href="http://www.amazon.com/HTML5-Up-Running-Mark-Pilgrim/dp/0596806027?ie=UTF8&tag=diveintomark-20&creativeASIN=0596806027">buy “HTML5: Up & Running” with this affiliate link</a> or <a href=http://oreilly.com/catalog/9780596806033>buy an electronic edition directly from O’Reilly</a>. You’ll get a book, and I’ll get a buck. I do not currently accept direct donations.
</blockquote>
</div>
</div>
<p class=c>Copyright MMIX–MMXI <a href=about.html>Mark Pilgrim</a>
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