HTML - Browser Support & Compatibility
Overview
Estimated time: 20–30 minutes
Principles
- Progressive enhancement: core content and functionality first.
- Feature detection: check APIs ("if ('fetch' in window)") instead of user-agent sniffing.
- Consult MDN BCD for support tables.
Examples
<script>
  if ('IntersectionObserver' in window) {
    // enhance
  } else {
    // fallback
  }
</script>
Exercises
- Audit one page and list enhancements that require feature detection; add checks and fallbacks.