seniorHTML5
How does 'Feature Detection' differ from 'User Agent Sniffing'?
Updated Apr 28, 2026
Short answer
Feature detection checks for specific capabilities; UA sniffing checks the browser name.
Deep explanation
UA sniffing is brittle because browser strings can be forged or changed. Feature detection (using JS or @supports in CSS) verifies if the actual functionality exists, which is the gold standard for progressive enhancement.
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