The Document Object Model is “an application programming interface (API) for valid HTML and well-formed XML documents. It defines the logical structure of documents and the way a document is accessed and manipulated” (from W3C).
- “An HTML page is rendered in a browser. The browser assembles all the elements(objects) that are contained in the HTML page, downloaded from web-server in its memory. Once done the browser then renders these objects in the browser window. Once the HTML page is rendered in web-browser window, the browser can no longer recognize individual HTML elements(Objects).”
- “The HTML objects, which belong to the DOM, have descending relationship with each other.”
- “The topmost object in DOM is Navigator (i.e. Browser) itself. The next level in DOM is browser’s Window. And next is Documents displayed in Browser’s Window.”
The image exemplifying the DOM is also from Wikipedia.
The whole specification from W3C of DOM Level 3, the current release of DOM: http://www.w3.org/TR/DOM-Level-3-Core/