1: <header> and <footer>
Although the html5 elements <header> and <footer> tags do not differ in terms of the actual display from the <div> tag, they will provide you with long-term benefits in search engine performance. These tags will let search engines know the difference between the actual “content” on the page, and important information which isn’t the actual content, i.e. header and footer information.
2: <video> and <audio>
3: <article> and <section>
There is often some confusion over the difference between the <article> element and the <section> element. Essentially, the <article> element is a specialised kind of <section>. An article represents an independent block of related content, with its own self-contained semantic meaning. Whereas a section is just a block of related content. A section has more semantic meaning than a <div> which is just a block of content.
4: <input> type attributes
The new <output> element is used in forms and represents the result of a calculation, like one performed by a script. It has a value attribute, supporting both global attributes and event attributes in HTML5. This new element is a much more convenient way of doing things than the previous way.
The new HTML5 addition, <canvas> tag, allows for dynamic, scriptable rendering of 2D shapes and bitmap images. While not perfect, it is still a great way to build things like graphs and 2D charts, and custom graphics, something which traditionally has been seen as a weak spot in HTML.
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