Which programming interface represents the structure of a web document?

The Document Object Model (DOM) is the programming interface that represents the structure of a web document. It reflects the document's structure as a tree of objects where each node corresponds to part of the document, such as elements, attributes, and text. This model allows scripts, such as those written in JavaScript, to manipulate the content, structure, and style of the web page dynamically.

In the context of web development, the DOM enables developers to access and modify the structure of a document, adding, removing, or altering elements on the page in real time. This interactivity is essential for creating modern web applications that respond to user input and change dynamically without requiring a full page reload.

API, while related to the way different software components interact, does not specifically represent the structure of a web document. CSS is primarily concerned with the presentation and styling of the document, rather than its structural representation. HTML provides the markup to create the document itself but does not serve as an interface for manipulation after the document is created, like the DOM does.