The HTML <aside> tag provides information about the main content. According to W3C definition, the <aside> element represents content that forms the main textual flow of a document.

HTML aside is a new tag introduced in HTML5.

HTML aside tag example

 <p>I don’t want to live in Ghaziabad, I wish; I could buy a flat in New Delhi.</p>
<aside>
  <h3>New Delhi</h3>
  <p>New Delhi is the capital of India.</p>
</aside>

Output:

I don’t want to live in Ghaziabad, I wish; I could buy a flat in New Delhi.

HTML aside tag also supports global and event attributes in HTML.