HTML

HTML (HyperText Markup Language) is the markup language that structures every website. Tim Berners-Lee developed HTML in 1991 at CERN as the foundation of the World Wide Web. HTML5 is today's current standard, maintained by WHATWG as a living specification ("living standard") rather than discrete versions. HTML is a semantic language: tags describe the meaning of content, not its appearance. An <h1> is the main heading, <article> a standalone article, <nav> navigation, <button> an interactive element. This semantics is the foundation for three things beyond HTML itself: screen-reader accessibility (WCAG, mandatory in the EU since 2025), SEO (Google uses semantic structure as a ranking signal), and maintainability (clearly structured HTML is still understandable years later). Modern development combines HTML with three layers: CSS for presentation (colors, layout, responsive behavior), JavaScript for interactivity (forms, dynamic content, APIs), and semantic HTML elements as the structural foundation. Frameworks like React, Vue, or Next.js ultimately also generate HTML — under the hood every website is HTML. Key best practices: correct heading hierarchy (one H1 per page, no jumps from H2 to H4), alt text for all images (accessibility + SEO), label-association in forms, correct input types for mobile keyboards (type="email", type="tel"), ARIA attributes only when semantic elements are insufficient. The most common mistakes: <div> soup instead of semantic elements, missing alt text, links styled as buttons and vice versa, multiple H1 per page, forms without labels. These mistakes are toxic for accessibility and cost SEO rankings. For GoldenWing projects: semantic HTML is the foundation of every web-design task, not optional.