1. <header>

The <header> element represents a group of introductory or navigational aids.
It may contain some heading elements and other elements like a logo, wrapped section's header, a search form and so on.
Example
  1. <header>
  2. <h1>Hello World </h1>
  3. <p>Its time to start HTML5 </p>
  4. </header>

2. <nav>

The <nav> element is intended only for a major block of navigation links.
So we can say that it represents a section of the document intended for navigation (like a menu).
Example
nav.html
  1. <nav>
  2. <ul>
  3. <li><a href="index.html">Home</a></li>
  4. </ul>
  5. </nav>
index.html
  1. <html>
  2. <head>
  3. My home page Abhi
  4. </head>
  6. <body>
  7. <p>Try it at home</p>
  8. <nav>
  9. <ul>
  10. <li><a href="nav.html" />Back</li></ul>
  11. </nav>
  12. </body>
  13. </html>

3. <section>

It represents a generic document or application section. It can be used together with the h1, h2, h3, h4, h5, and h6 elements to indicate the document structure. (Just a logical grouping such as a contents section.)
Example
  1. <html>
  2. <body>
  3. <section>
  4. <h1>Good Morning</h1>
  5. <p>
  6. Hello world
  7. </p>
  8. </section>
  9. <section>
  10. <h1>Good Evening </h1>
  11. <p>
  12. Bye Bye World.</p>
  13. </section>
  14. </body>
  15. </html>

4. <article>

It represents an independent piece of contents of a document, such as a blog entry or newspaper article.
Example
  1. <html>
  2. <body>
  4. <article>
  5. <h1>HTML5 with Abhijeet</h1>
  6. <p>Today we will start HTML5 </p>
  7. </article>
  8. <article>
  9. <h1>HTML5 news part with Abhijeet</h1>
  10. <p>Great News for you.. </p>
  11. </article>
  13. </body>
  14. </html>

5. <aside>

It represents a piece of content that is only slightly related to the rest of the page. (Usually a sidebar, but could be another type of content that isn't directly related to the main content.)
Example
  1. <html>
  2. <head><title>HTML5 with Abhijeet</title>
  3. <style type="text/css"">
  4. aside
  5. {
  7. font-style:italic;
  8. color:cyan;
  9. float:right;
  10. width:80%;
  12. }
  13. </style>
  14. </head>
  15. <body>
  16. <div>
  17. <aside>Its raining...
  18. </aside>
  19. <p>Hello world</p>
  20. </div>
  21. </body>
  22. </html>

6. <footer>

Represents a footer for a section and can contain information about the author and copyright information.
Example
  1. <html>
  2. <body>
  4. <footer>
  5. <p>written by: Abhijeet Singh</p>
  6. <p>Contact information: <a href="mailto:[email protected]">[email protected]</a>.</p>
  7. </footer>
  9. </body>
  10. </html>