I feel that HTML 5 has many useful features for creating better websites. The new structural tags including: ‘section,’ ‘aside,’ ‘header,’ ‘footer’ and ‘nav’ provide better ways of managing the content on your page. The DOCTYPE declaration is simplified and the ‘autofocus’ and ‘required’ attributes have proven to be helpful. The ‘canvas’ feature is a very good way to plot data with specific points. CSS3, has many new selectors for controlling the appearance of content. There are many new ways to specifically locate elements in the markup. The ‘nth-child’ is helpful for selecting specific occurrences of items in a list. The ‘a[alt]’ selector is good for locating items with a specific prefix or suffix. The ‘:not’ function is useful for choosing class names that do not have a specific name. The gradient features have proven to be useful allowing specific control on when to begin and end the gradient and the specific colors to use. The @font-face is good as well. And with the use of fontsquirrel.com, with proper permission, there is a large variety of fonts in which to choose that are portable with the web site. Rounded corners, of course, are a good feature. And the transition selector to enlarge an image on hover has proven to very valuable. And media queries are helpful for changing styling due to specific screen or device widths.
I enjoy the ‘canvas’ and ‘transition’ features the most. And I feel the border-radius, @font-face and media queries are features I would use for regular workflow.