Many web sites contain HTML code like: <div id="nav"> <div class="header"> <div id="footer"> to indicate navigation, header, and footer.

In HTML there are some semantic elements that can be used to define different parts of a web page:  

• <article>
• <aside>
• <details>
• <figcaption>
• <figure>
• <footer>
• <header>
• <main>
• <mark>
• <nav>
• <section>
• <summary>
• <time>