Elements

HTML documents are made up by HTML elements.

HTML elements are written with a start tag, with an end tag, with the content in between: <tagname>content</tagname>, The HTML element is everything from the start tag to the end tag.

Nested

HTML elements can be nested (elements can contain elements). All HTML documents consist of nested HTML elements.

Empty HTML Elements

HTML elements with no content are called empty elements. <br> is an empty element without a closing tag (the <br> tag defines a line break). Empty elements can be "closed" in the opening tag like this: <br />.