IconVault's Page Lifecycle Playground visualizes the real page lifecycle state machine: active, passive, hidden, frozen, terminated and discarded, with live visibility tracking, freeze and resume simulation, bfcache eligibility checks that flag what blocks back-forward cache, and a full event log of every transition. It is free and runs fully in your browser.

You will learn why the old `unload` event is unreliable on mobile and what to use instead: `pagehide`, `visibilitychange` and `freeze` for saving state. The lab shows how to make pages bfcache-friendly (no unload listeners, careful with open connections), how frozen pages stop timers and network, and the resume pattern that restores state when the user navigates back.