Expression Web 4 now has the HTML5 Doctype available, however, you won't find a single HTML5 Element anywhere. The most likely reason for this is because HTML 5 is not yet a Web Standard, and since EW prides itself on making Compliant Web Sites....adding the currently "Not Compliant" elements makes sense.
That doesn't mean we cannot use HTML5. After all, CSS 2.1 became a Web Standard in June 2011, yet we've been using CSS 2.1 for several years. Waiting for HTML5 to officially become a Web Standard is foolish. Doing so will put you behind the rest.
Most of the modern browsers support a good amount of the HTML5 specification, yet there is still a long way to go until HTML5 is complete (if ever it will be completed....it's more of an evolutionary process).
The New HTML5 Elements are not supported by any version of Internet Explorer except IE9. IE9 does support some HTML5. However, it will be a few years from now until no one uses IE7 & 8.
To find out what is supported by which browser, go to http://caniuse.com "Can I Use".
So.... Can we still Use HTML5?
Yes, we can.
But can we use HTML5 right now?
Yes, we can.
And, there is even a way to force Internet Explorer, our problem child, to render HTML5 elements. We'll get to that much later. First, we need to review the core HTML5 Elements.
The above elements will be used to create a Layout in HTML5. We will continue to use the div tag in situations where we need a container simply for purposes of Styling and achieving design goals.
The way we use HTML5 Elements is dependent upon the Content. Each HTML5 Element has Content Requirements.
For instance, the article element is used for content that is "independent" of it's surroundings. It is content that can stand on its own should we pluck it out of the web page.
However, the aside element is used for content that is "tangentially related" to the surrounding content.
Let's take a look at the HTML5 Elements a little more closely. 