Document Structure

Document Skeleton

The Browser Builds a Page

A minimal HTML document enters standards mode, declares a language, sets the browser title, and finally paints a heading.

Program

HTML is declarative: each element describes document structure and the browser turns that structure into rendered output.

The browser keeps structure first; paint comes after body nodes exist.Document skeleton to DOMPinned nodes from document_skeleton.htmlhtmllang=enheadmetadatabodyvisibletitletab textmainregionh1headingThe browser keeps structure first; paint comes after body nodes exist.
Figure: HTML document structure becomes a DOM tree. Model source: books/html/01document_structure/document_skeleton/diagrams/dom_tree.semantic.json.
document_skeleton.html 
<!doctype html>
<html lang="en">
<head>
  <title>Launch Checklist</title>
</head>
<body>
  <h1>Launch Checklist</h1>
</body>
</html>
doctype The doctype asks the browser to parse the document in standards mode.
document title The title element updates browser chrome before body content is visible.