Consistency enables teams to navigate templates quickly and automated tools to enforce policies.
Formatting
- Indent nested blocks uniformly (two spaces is common).
- Wrap long attribute lists one attribute per line.
- Close void elements without slashes unless integrating XML pipelines.
Attribute ordering (example)
id → class → data-* → aria-* → event handlers—pick a documented order.
Linting & validation
- HTML validators catch stray tags and illegal nesting.
- Accessibility lint rules spot missing labels, low contrast (via integrations), invalid ARIA.
Documentation
Embed rationale comments near unusual markup (server-side comments preferred over client-visible HTML comments).
Performance hygiene
- Remove commented-out markup before shipping.
- Avoid enormous inline SVG blobs inside unrelated templates—split partials.
Why conventions pay rent
Uniform attribute ordering and naming reduce diff noise in large teams—time spent bikeshedding style is time not spent on security and accessibility reviews.
Example — readable attribute wrapping
<!-- Packed (hard to review in PRs) -->
<img src="/images/baby-icon.webp" alt="Course sample icon" width="120" height="80" loading="lazy" class="rounded-2xl">
<!-- Wrapped (diff-friendly) -->
<img
class="rounded-2xl shadow-sm"
src="/images/baby-icon.webp"
alt="Rounded baby-face illustration from the course asset pack"
width="525"
height="350"
loading="lazy"
>Rendered (/public/images/baby-icon.webp)
Pick one house style; Prettier plugins can enforce it.
Important interview questions and answers
- Q: What is the safest default character encoding for modern HTML?
A: UTF-8, declared early with `` and matched by server `Content-Type` headers. - Q: When are HTML entities still useful in UTF-8 pages?
A: For reserved characters (`&`, `<`) and contexts where explicit escaping avoids parser ambiguity. - Q: What is the key difference between HTML5 parsing and XHTML parsing?
A: HTML5 recovers from many errors; XHTML (XML) treats many parse errors as fatal.
Tip: Lowercase tags, quoted attributes, and consistent indentation aid reviews.