An HTML element is defined by a starting tag. If the element contains other content, it ends with a closing tag, where the element name is preceded by a forward slash as shown below with few tags −
|Start Tag||Content||End Tag|
|<p>||This is paragraph content.||</p>|
|<h1>||This is heading content.||</h1>|
|<div>||This is division content.||</div>|
So here <p>....</p> is an HTML element, <h1>...</h1> is another HTML element. There are some HTML elements which don't need to be closed, such as <img.../>, <hr /> and <br /> elements. These are known as void elements.
HTML documents consists of a tree of these elements and they specify how HTML documents should be built, and what kind of content should be placed in what part of an HTML document.
HTML Tag vs. Element
An HTML element is defined by a starting tag. If the element contains other content, it ends with a closing tag.
For example, <p> is starting tag of a paragraph and </p> is closing tag of the same paragraph but <p>This is paragraph</p> is a paragraph element.
Nested HTML Elements
It is very much allowed to keep one HTML element inside another HTML element −
<!DOCTYPE html> <html> <head> <title>Nested Elements Example</title> </head> <body> <h1>This is <i>italic</i> heading</h1> <p>This is <u>underlined</u> paragraph</p> </body> </html>