Definition of HTML "property"

A property is a simple data structure consisting of a name and a value, also known as a name-value pair. An HTML property is a characteristic of something in an HTML document. In HTML, a property always has some value, possibly null or empty, that might come from its default value, an inherited value or a value explicitly set by an attribute on an HTML tag.

The HTMLPropertiesCollection interface provides access to a collection of properties.