The Past, Present, and Future of HTML5

Stop and think for a moment about how long you've been a developer. For some of you, that journey started recently. For others, it has been years. However long it's been, do you realize that less than a decade ago, the .NET revolution had not officially started? Classic ASP was the primary way we developed for the web, and HTML was at version—wait a minute—is still at version 4.01!

Despite sluggish transformations regarding HTML overall, small to very dramatic changes in technologies that are based on HTML have occurred. Think of the changes that have occurred in web browsers, JavaScript, and Cascading Style Sheets (CSS). Think of how AJAX has changed the way many web developers approach communications between the browser and server-side resources. The web has seen many changes but with virtually no change to its core language, HTML. However, that logjam is about to bust with HTML5.

A Brief History of HTML5

Before we discuss what HTML5 has to offer, we should note that attempts have been made to change HTML. Note the word is change, not upgrade or revise. But what does that mean? Why is it important to consider the failed attempts to change HTML? So that you can appreciate why HTML5 is worth investigating and why it is here to stay. For these reasons, let's take a brief journey down memory lane and consider the series of events that led to where we are today. Then we'll discuss where we'll be tomorrow.

You probably already know who Tim Berners-Lee is and that HTML came into existence as far back as 1989. You also probably know that the Internet took off in the 1990s, and so on. So instead of strolling through a step-by-step timeline, let's focus on the attempts to replace HTML with something else.

Fast-forward to January 2000. The World Wide Web Consortium (W3C) recommended Extensible HyperText Markup Language (XHTML) 1.0. For an XHTML document to be served correctly, the author had to use the new application/xhtml+xml MIME type. However, Appendix C of W3C's XHTML 1.0 specification made provision for pages to be served by using the common text/html MIME type.

More than a year later, in May 2001, the W3C recommended XHTML 1.1. The abstract of the recommendation stated, "The purpose of this document type is to serve as the basis for future extended XHTML 'family' document types, and to provide a consistent, forward-looking document type cleanly separated from the deprecated, legacy functionality of HTML 4 that was brought forward into the XHTML 1.0 document types."

According to the abstract, XHTML was prepped to be the future of the web. The abstract boldly referred to HTML 4 as "deprecated, legacy functionality." And version 1.1 of XHTML removed the Appendix C version 1.0 provision that allowed a page to be served with the text/html MIME type. So why didn't this recommended standard replace HTML altogether? The answer is simple: Developers didn't implement it.

To be sure, many developers tried to implement XHTML in their websites. XHTML mandated a well-formed XML document using the classic HTML tags. To be well-formed, a web page would need to be served with no overlapping tags and no missing end tags, and the values of all attributes had to be enclosed in quotation marks. The notion of cleaning up our web pages wasn't unpopular, but it wasn't strictly enforced either. And even if a web developer created a well-formed web document, was it served with the application/xhtml+xml MIME type? Likely not. In fact, it is estimated that 99 percent of web pages on the Internet today contain at least one violation of the XHTML standard, which, if enforced, would cause the page to stop rendering and post an error to the end user. Ouch!

So now what? Exactly. WHAT was born. The Web Hypertext Applications Technology (WHAT) Working Group, actually known as WHATWG, came into existence in 2004 to put life back into HTML. This group's intent was to move forward in a manner consistent with how the web was actually being used and to spearhead innovations in HTML while maintaining backward compatibility. Instead of breaking 99 percent of the web, why not embrace the way in which web pages are actually served? Browsers have been forgiving. Why make page-breaking changes?

Therefore, the WHATWG came up with Web Applications 1.0 while the W3C worked toward version 2.0 of XHTML. However, near the end of 2006, it was clear that the WHATWG was gaining momentum while XHTML 2.0 was lacking support by any major browser. Thus, the W3C announced it would collaborate with the WHATWG. One of the outcomes of this union was to rename Web Applications 1.0 as HTML5.

Is there a lesson in this for us? Absolutely. Despite noble aims and grand ambitions, whatever the masses choose to adopt wins. The growing adoption of HTML5 makes it the winner. HTML5 cannot be ignored. Our brief history lesson demonstrates that HTML5 is here because we willed it to be here. (For more in-depth coverage of the history leading up to HTML5, check out Mark Pilgrim's Dive Into HTML5.)

Start Using HTML5

Although HTML5 is not an official specification yet, it achieved WC3 Candidate Recommendation status as of December 2012, which means that HTML5 is on the cusp of being the industry standard for web development. HTML5 already has a prominent place in website development, given that the major browsers are incorporating HTML5 features and Microsoft's recently stated intention to incorporate native HTML5 in Windows. In light of these changes, it's a good idea to start getting familiar with HTML5 now—and you can do so without making dramatic changes to the pages you already have. Let's consider a minimalistic HTML5 document, such as in Figure 1.

Hello World!

Notice the omission of the and tags. According to the current specs, this is still a valid document. If these tags are omitted, the browser will still parse the document, and the tags will be implied. This represents a shift from the strict conformity imposed by the current HTML standard.

Here is another example of how easy it is to adapt to HTML5:

The doctype syntax has been simplified. Compare this to examples of what we have been accustomed to, shown in Figure 2.

The doctype declaration is required. Although it is clearly easier to type the normal HTML5 doctype, the deprecated doctypes in Figure 2 are still accepted formats. By the way, the doctype declaration is not case sensitive, so any of the following are acceptable:

Now take a look at Figure 3 to see a more realistic starting point for an HTML5 document.

  
    
    
  
  
    
Simple text.
  

You might find slight differences in this HTML5 document compared to what you are used to. Apart from the doctype, you might notice the attribute on the tag and the contents of the tag. Let's focus first on the tag:

The lang="en" attribute informs the browser that the contents of this document are in English. This is much simpler than the following:

Look at how much was removed. There is no longer any need to specify the namespace of the document because all elements in HTML5 (unless otherwise noted) belong to the XHTML namespace. The xml:lang attribute is left over from the XHTML era. So, once again, HTML5 presents a simpler way to do things, but for what it is worth, the older syntax is still acceptable.

Now, how about that tag? This is how we used to handle it:

And as you have noticed, it is now this simple:

Of course if you want to use the old style, that's still okay. It's a good practice to make this meta charset tag the first child of the tag because the specification states that the character encoding declaration must appear within the first 1024 bytes of the document. Why set the encoding for the document? Failing to do so can cause security vulnerabilities. Although the encoding can also be set in the HTTP headers, it's still a good practice to declare the encoding in the document.

These subtle differences clearly confirm the WHATWG's commitment to maintaining backward compatibility while allowing changes that simplify or enhance HTML. However, not everything from the past is preserved in HTML5. For good reason, some tags, such as those in Figure 4, have been given a proper burial.