HTML Interview Questions and Answers
HTML questions check whether you write structured, accessible markup. Here are the common ones, answered.
What is semantic HTML and why does it matter?
Semantic elements (header, nav, main, article, footer) describe meaning, not just appearance. It matters for accessibility (screen readers navigate by landmarks), SEO, and maintainability.
What's the difference between async and defer on a script?
Both download in parallel without blocking parsing. async runs as soon as it's ready (order not guaranteed) — good for analytics. defer runs after parsing, in order — best for app scripts that touch the DOM.
What is the DOM?
The Document Object Model — a tree of node objects the browser builds from your HTML. JavaScript reads and mutates the DOM to change the page after load.
What are ARIA roles and when do you use them?
ARIA attributes describe custom widgets to assistive tech when no native element fits. Prefer native elements first — 'no ARIA is better than bad ARIA'. Use it only to fill gaps.
localStorage vs sessionStorage vs cookies?
localStorage persists until cleared; sessionStorage lasts for the tab; cookies are small (~4KB) and sent to the server on every request. Prefer httpOnly cookies for auth tokens.
Why is the viewport meta tag important?
Without <meta name=viewport content='width=device-width, initial-scale=1'>, mobile browsers render at a fake ~980px width and zoom out, so your responsive CSS won't apply.
Get interview-ready on HTML & CSS
Semantics, accessibility, forms and the critical rendering path — in the HTML & CSS Handbook (Complete Frontend Kit).
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- Is HTML really asked in interviews?
- Yes — semantics, accessibility, script loading and the DOM come up, especially at companies that value quality markup.
- What HTML topics should I focus on?
- Semantic elements, accessibility/ARIA basics, forms, responsive images, and how the browser builds the page.