8. “How can I start using HTML5 if older browsers don’t support it?” But the question
itself is misleading. HTML5 is not one big thing; it is a collection of individual
features.
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9. you can’t detect “HTML5 support,” because that doesn’t make any sense. But you can
detect support for individual features, like canvas, video, or geolocation.
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10. You may think of HTML as tags and angle brackets. That’s an important part of it, but
it’s not the whole story. The HTML5 specification also defines how those angle
brackets interact with JavaScript, through the Document Object Model (DOM).
HTML5 doesn’t just define a <video> tag; there is also a corresponding DOM API for
video objects in the DOM. You can use this API 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
<video> tag itself.
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11. Unlike previous versions of HTML and XHTML, which are defined in terms
of their syntax, HTML 5 is being defined in terms of the Document Object
Model (DOM)—the tree representation used internally by browsers to
represent the document.
Every XML and HTML document in an HTML UA is represented by a
Document object.
The advantage of defining HTML 5 in terms of the DOM is that the language
itself can be defined independently of the syntax. There are primarily two
syntaxes that can be used to represent HTML documents: the HTML
serialisation (known as HTML 5) and the XML serialisation (known as
XHTML 5).
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21. <section> A section, or section of a chapter of text, or a book.
<header> The page header. This is not the same as the <head> element.
<footer> The footer of the page. Typically where all the legal crapola goes.
<nav> Navigation links to other pages. You could put your websites navigation
in this for example.
<article> A blog article could be encapsulated by this for example.
<aside>The aside tag can be used to provide extra information for a block of
text. Much like sidebar material in books etc
<figure>The <figure> element can be used to annotate your main text with
diagrams, which aren’t necessarily imperative to the text.
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31. Modernizr is an open source, MIT-licensed JavaScript library that detects
support for many HTML5 and CSS3 features. At the time of writing, the latest
version is 1.1. You should always use the latest version. To do so, include the
following <script> element at the top of your page:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Dive into HTML5</title>
<script src="modernizr.min.js"></script>
</head> <body> ...
</body> </html>
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