H1H6

H1 through H6 are the six heading elements in HTML that define the hierarchy of content on a web page. They range from h1, the top-level heading, to h6, the least prominent. In typical usage, h1 denotes the main page title, and sections are organized with h2 through h6 to reflect nested structure.

Semantics and usage: Heading elements convey document structure to both users and software. A page generally should include one h1 element representing the main topic, followed by headings that descend in a logical order. Skipping levels (for example, jumping from h2 to h4) is discouraged because it can confuse screen readers and disrupt the outline.

Accessibility: Properly nested headings help keyboard and screen reader users navigate the page. Text within headings should be concise and descriptive; avoid empty headings or redundant phrasing. Do not rely on headings solely for visual styling.

Styling and CSS: Browsers apply default sizes and weights to h1–h6, but authoring should separate structure from presentation. Use CSS to control typography and spacing while preserving the semantic meaning of each heading level.

SEO and interoperability: Search engines use headings to gauge page topics and hierarchy; clear, descriptive headings can improve comprehension and indexing. While some older tooling attempted to reconstruct outlines, current practice emphasizes semantic markup over visual cues.

History and notes: The h1–h6 elements are part of HTML from early specifications and remain standard in HTML5. Some document outlines are not fully exposed by all user agents, but correct heading structure remains important for accessibility and content organization.