8.5 — Validation & Developer Tools
Even broken HTML often renders. The browser’s silent error‑correction hides mistakes, but those mistakes still degrade accessibility, performance, and maintainability. Professional engineers rely on validators and developer tools to expose the gap between what they wrote and what the browser actually built.
TAKEAWAY
Validate your source with the W3C Nu HTML Checker before deployment. Understand that View Source shows the truth; the Elements panel shows the browser’s corrected version. These two practices – automated validation and source‑level awareness – are the final line of defense between a fragile prototype and an industrial‑grade, future‑proof web application.