Meridian Proctor · lockdown runtime

Whole-screen enforcement that a candidate cannot walk around.

A reference implementation of the Fullscreen and Keyboard Lock APIs for a multi-step proctored assessment in Next.js 16 — built so no route change, reload or Escape key can leave the exam rendered in a windowed browser.

• Gesture-safe entry

  requestFullscreen() fires as the first synchronous statement of the click handler — before any await, router.push or fetch — so Transient User Activation is never spent.

• Zero-escape shield

  Any moment the document is armed but not fullscreen, an opaque top-layer overlay traps focus, swallows keystrokes and disables the editor.

• Reload survival

  Armed state lives in sessionStorage. A refresh drops fullscreen but comes back armed and breached, so the shield paints on first render.

• Opportunistic re-lock

  Every pointerdown and keydown while breached is a fresh activation, quietly reused to restore fullscreen and re-apply the keyboard lock.

Open the invite in its own browser tab. Fullscreen and Keyboard Lock are restricted inside iframes, and Keyboard Lock requires a Chromium browser on a secure top-level context.