Document Object Model (DOM)

The Document Object Model (DOM)The Document Object Model (DOM) is the structured representation of a web page that a browser uses to hold its content and structure in memory. JavaScript can modify the DOM to add or remove content.Open glossary entry → is the tree-like structure a browser uses to represent a page internally. Every element, such as a heading, paragraph or image, is a node in this tree. JavaScript accesses the DOM and can change it dynamically.

For search engine optimisationSearch Engine Optimization (SEO) covers all measures that help a website become more visible in unpaid (organic) search results.Open glossary entry →, an important distinction matters:

• The page source shows the HTMLHyperText Markup Language (HTML) is the markup language for web pages. It defines the structure and content of a page, such as headings, paragraphs, links and images.Open glossary entry → originally delivered by the server.
• The rendered DOM shows the state after JavaScript has run, as displayed by the developer tools (DevTools).

These two can differ. If content exists only in the rendered DOM but not in the raw source, it may be invisible to simple crawlers and many AI crawlersAI crawlers are automated bots that fetch web pages for AI providers in order to find content, make it available for search functions, retrieve it for answers, or, depending on the provider, use it for model training.Open glossary entry →. When auditing, you should therefore compare the source with the rendered DOM rather than relying on the browser view alone.