> For the complete documentation index, see [llms.txt](https://johnkazer.gitbook.io/core-web-dev-concepts/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://johnkazer.gitbook.io/core-web-dev-concepts/setup/html-css-and-browsers.md).

# HTML, CSS and Browsers

Browsers host the DOM, or document object library, which is a text data structure representing the HTML used to build the web page. The browser applies CSS content and manages relationships with JavaScript and to its API.