As you learn HTML5 and add new techniques to your toolbox, you’re likely going to want to build yourself a blueprint, or boilerplate, from which you can begin all your HTML5-based projects. In fact, you’ve probably already done something similar for your existing XHTML or HTML 4.0 projects.
We encourage this, and you may also consider using one of the many online sources that provide a basic HTML5 starting point for you.
In this project, however, we want to build our code from scratch and explain each piece as we go along. Of course, it would be impossible for even the most fantastical and unwieldy sample site we could dream up to include every new element or technique, so we’ll also explain some new features that don’t fit into the project. This way, you’ll be familiar with a wide set of options when deciding how to build your HTML5 and CSS3 websites and web apps, so you’ll be able to use this book as a quick reference for a number of techniques.
Let’s start simple, with a bare-bones HTML5 page:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>The HTML5 Herald</title>
<meta name="description" content="The HTML5 Herald">
<meta name="author" content="SitePoint">
<link rel="stylesheet" href="css/styles.css?v=1.0">
<!--[if lt IE 9]>
<script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script>
<![endif]-->
</head>
<body>
<script src="js/scripts.js"></script>
</body>
</html>Look closely at the above markup. If you’re making the transition to HTML5 from XHTML or HTML 4, then you’ll immediately notice quite a few areas in which HTML5 differs.
The Doctype
First, we have the Document Type Declaration, or doctype. This is simply a way to tell the browser—or any other parsers—what type of document they’re looking at. In the case of HTML files, it means the specific version and flavor of HTML. The doctype should always be the first item at the top of all your HTML files. In the past, the doctype declaration was an ugly and hard-to-remember mess. For XHTML 1.0 Strict:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">And for HTML4 Transitional:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">Over the years, code editing software began to provide HTML templates with the doctype already included, or else they offered a way to automatically insert one. And naturally, a quick web search will easily bring up the code to insert whatever doctype you require.
Although having that long string of text at the top of our documents hasn’t really hurt us (other than forcing our sites’ viewers to download a few extra bytes), HTML5 has done away with that indecipherable eyesore. Now all you need is this:
<!doctype html>Simple, and to the point. You’ll notice that the “5” is conspicuously missing from the declaration. Although the current iteration of web markup is known as “HTML5,” it really is just an evolution of previous HTML standards—and future specifications will simply be a development of what we have today. Because browsers have to support all existing content on the Web, there’s no reliance on the doctype to tell them which features should be supported in a given document.
The html Element
Next up in any HTML document is the html element, which has not changed significantly with HTML5. In our example, we’ve included the lang attribute with a value of en, which specifies that the document is in English. In XHTML-based syntax, you’d be required to include an xmlns attribute. In HTML5, this is no longer needed, and even the lang attribute is unnecessary for the document to validate or function correctly.
So here’s what we have so far, including the closing </html> tag:
<!doctype html>
<html lang="en">
</html>The head Element
The next part of our page is the <head> section. The first line inside the head is the one that defines the character encoding for the document. This is another element that’s been simplified. Here’s how you used to do this:
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">HTML5 improves on this by reducing the character encoding <meta> tag to the bare minimum:
<meta charset="utf-8">In nearly all cases, utf-8 is the value you’ll be using in your documents. A full explanation of character encoding is beyond the scope of this chapter, and it probably won’t be that interesting to you, either. Nonetheless, if you want to delve a little deeper, you can read up on the topic on the W3C’s site.
To ensure that all browsers read the character encoding correctly, the entire character encoding declaration must be included somewhere within the first 512 characters of your document. It should also appear before any content-based elements (like the <title> element that follows it in our example site).
There’s much more we could write about this subject, but we want to keep you awake—so we’ll spare you those details! For now, we’re content to accept this simplified declaration and move on to the next part of our document:
<title>The HTML5 Herald</title>
<meta name="description" content="The HTML5 Herald">
<meta name="author" content="SitePoint">
<link rel="stylesheet" href="css/styles.css?v=1.0">In these lines, HTML5 barely differs from previous syntaxes. The page title is declared the same as it always was, and the <meta> tags we’ve included are merely optional examples to indicate where these would be placed; you could put as many meta elements here as you like.
The key part of this chunk of markup is the stylesheet, which is included using the customary link element. At first glance, you probably didn’t notice anything different. But customarily, link elements would include a type attribute with a value of text/css. Interestingly, this was never required in XHTML or HTML 4—even when using the Strict doctypes. HTML5-based syntax encourages you to drop the type attribute completely, since all browsers recognize the content type of linked stylesheets without requiring the extra attribute.
Leveling the Playing Field
The next element in our markup requires a bit of background information before it can be introduced.
HTML5 includes a number of new elements, such as article and section, which we’ll be covering later on. You might think this would be a major problem for older browsers, but you’d be wrong. This is because the majority of browsers don’t actually care what tags you use. If you had an HTML document with a <recipe> tag (or even a <ziggy> tag) in it, and your CSS attached some styles to that element, nearly every browser would proceed as if this were totally normal, applying your styling without complaint.
Of course, this hypothetical document would fail to validate, but it would render correctly in almost all browsers—the exception being Internet Explorer. Prior to version 9, IE prevented unrecognized elements from receiving styling. These mystery elements were seen by the rendering engine as “unknown elements,” so you were unable to change the way they looked or behaved. This includes not only our imagined elements, but also any elements which had yet to be defined at the time those browser versions were developed. That means (you guessed it) the new HTML5 elements.
At the time of writing, Internet Explorer 9 has only just been released (and adoption will be slow), so this is a bit of a problem. We want to start using the shiny new tags, but if we’re unable to attach any CSS rules to them, our designs will fall apart.
Fortunately, there’s a solution: a very simple piece of JavaScript, originally developed by John Resig, can magically make the new HTML5 elements visible to older versions of IE.
We’ve included this so-called “HTML5 shiv”in our markup as a <script> tag surrounded by conditional comments. Conditional comments are a proprietary feature implemented by Microsoft in Internet Explorer. They provide you with the ability to target specific versions of that browser with scripts or styles. This conditional comment is telling the browser that the enclosed markup should only appear to users viewing the page with Internet Explorer prior to version 9:
<!--[if lt IE 9]>
<script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script>
<![endif]-->It should be noted that if you’re using a JavaScript library that deals with HTML5 features or the new APIs, it’s possible that it will already have the HTML5 enabling script present; in this case, you could remove reference to Remy Sharp’s script. One example of this would be Modernizr, a JavaScript library that detects modern HTML and CSS features—and which we cover in Appendix A, Modernizr. Modernizr includes code that enables the HTML5 elements in older versions of IE, so Remy’s script would be redundant.
Of course, there’s still a group of users who won’t benefit from Remy’s HTML5 shiv: those who have, for one reason or another, disabled JavaScript. As web designers, we’re constantly told that the content of our sites should be fully accessible to all users, even those without JavaScript. When between 40% and 75% of your audience uses Internet Explorer, this can seem like a serious concern.
But it’s not as bad as it seems. A number of studies have shown that the number of users that have JavaScript disabled is low enough to be of little concern.
In one study conducted on the Yahoo network, published in October 2010, users with JavaScript disabled amounted to around 1% of total traffic worldwide. Another study indicated a similar number across a billion visitors. In both studies, the US had the highest number of visitors with JavaScript disabled in comparison to other parts of the world.
There are ways to use HTML5’s new elements without requiring JavaScript for the elements to appear styled in nonsupporting browsers. Unfortunately, those methods are rather impractical and have other drawbacks.
If you’re still concerned about these users, it might be worth considering a hybrid approach; for example, use the new HTML5 elements where the lack of styles won’t be overly problematic, while relying on traditional elements like divs for key layout containers.
The Rest is History
Looking at the rest of our starting HTML5 template, we have the usual body element along with its closing tag and the closing </html> tag. We also have a reference to a JavaScript file inside a script element.
Much like the link element discussed earlier, the <script> tag does not require that you declare a type attribute. In XHTML, to validate a page that contains external scripts, your <script> tag should look like this:
<script src="js/scripts.js" type="text/javascript"></script>Since JavaScript is, for all practical purposes, the only real scripting language used on the Web, and since all browsers will assume that you’re using JavaScript even when you don’t explicitly declare that fact, the type attribute is unnecessary in HTML5 documents:
<script src="js/scripts.js"></script>We’ve put the script element at the bottom of our page to conform to best practices for embedding JavaScript. This has to do with the page loading speed; when a browser encounters a script, it will pause downloading and rendering the rest of the page while it parses the script. This results in the page appearing to load much more slowly when large scripts are included at the top of the page before any content. This is why most scripts should be placed at the very bottom of the page, so that they’ll only be parsed after the rest of the page has loaded.
In some cases (like the HTML5 shiv) the script may need to be placed in the head of your document, because you want it to take effect before the browser starts rendering the page.
[3] A few you might want to look into can be found at http://www.html5boilerplate.com/ and http://html5reset.org/.
[4] You might be more familiar with its alternative name: the HTML5 shim. Whilst there are identical code snippets out there that go by both names, we’ll be referring to all instances as the HTML5 shiv, its original name.
Source Link: http://www.sitepoint.com/a-basic-html5-template/