main tag specifies the main content of the document. The content in the
main element should be unique to the document. It should not contain content that appears repeatedly throughout the document, such as sidebars, navigation bars, copyright information, site logos, or search forms.
Note: More than one main element cannot appear in a document. The main element cannot be a descendant of: article, aside, footer, header, or nav.
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8" /><title>Using main</title></head><body><header>My page</header><nav> [url=#]Home[/url]</nav><main> <article> <h1>My article</h1> Content </article> <aside> More information </aside></main><footer>Copyright 2013</footer></body></html>
Another example:
<h1>Skateboards</h1> The skateboard is the way cool kids get around <article> <h2>Longboards</h2> Longboards are a type of skateboard with a longer wheelbase and larger, softer wheels. ... ... </article> <article> <h2>Electric Skateboards</h2> These no longer require the propelling of the skateboard by means of the feet; rather an electric motor propels the board, fed by an electric battery. ... ... </article> </main> <!-- other content -->
The main tag is newly added in HTML 5
the main element