Definition of "inner HTML"

Inner HTML is the HTML content between the > at the end of the starting tag of an element and the < at the beginning of the ending tag of the same element (but not a void element), not including the tags themselves. The inner HTML is usually either flow content or phrasing content, depending on the content model of the element.

For example, in the following HTML code:

<p>Humpty Dumpty sat on a wall.<br/>
   Humpty Dumpty had a great fall.</p>

"Humpty Dumpty sat on a wall." and "Humpty Dumpty had a great fall." with its leading whitespace are two groups of text content that, along with the <br/> tag is some phrasing content that makes up the inner HTML of the p element for the paragraph.