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

1. Audit one page and list enhancements that require feature detection; add checks and fallbacks.