iOS Safari Protection

Purpose-built for Safari's jetsam process killer. Detects pressure signals and acts before the browser kills your tab.

Signals Monitored

Signal	Detection	Response
Page backgrounded	`visibilitychange`, `pagehide`, `blur`	Freeze all iframes
Low priority + background	Same events	Destroy (not just freeze)
FPS drop < 20	rAF timing analysis	Downgrade quality
FPS drop < 10	Sustained low FPS	Freeze all but highest priority
GC pause > 200ms	Frame delta spike	Memory warning
Tab previously killed	`document.wasDiscarded`	Restart at minimal quality
Memory nearing limit	Preflight estimation	Block new iframe loads

Configuration

new IframeShield({
  ios: {
    crashPrevention: true,
    backgroundFreeze: true,
    backgroundDestroyLowPriority: true,
    memoryWarningThreshold: 0.7,
    aggressiveCleanup: true,
    maxMemoryMB: 1200,
  },
});

Important: iOS Safari has no performance.memory API. Memory detection relies on FPS analysis, GC pause detection, and allocation timing probes.