Nested HTML Elements

HTML elements can be nested (elements can contain elements).

All HTML documents consist of nested HTML elements.

This example contains four HTML elements:

My First Heading

My first paragraph.

Empty HTML Elements

HTML elements with no content are called empty elements.

is an empty element without a closing tag (the
tag defines a line break).

Empty elements can be “closed” in the opening tag like this:

HTML5 does not require empty elements to be closed. But if you want stricter validation, or if you need to make your document readable by XML parsers, you must close all HTML elements properly.

Use Lowercase Tags

HTML tags are not case sensitive:

means the same as


The HTML5 standard does not require lowercase tags, but W3C recommends lowercase in HTML and demands lowercase for stricter document types like XHTML.

The element defines the whole document.

It has a start tag and an end tag .

The element content is another HTML element (the element).