Single-Textarea Proof-of-Concept

Testing native browser editing behavior (Lighthouse template, rectangular safe zone)

CANVAS: Lighthouse (lighthouse_01) — 800 × 10800 chars
Lighthouse Stationery

Live Telemetry

Active Element
BODY
Selection State
[0, 0] Len: 0
Focus Cycles
Gain: 0 | Loss: 0
Mouse Clicks
0
Last Click → Caret Placement
Click: (0px, 0px) → Resolved Index: 0
Characters
0
Paragraphs
1

Proof-of-Concept Test Sequence:

  • Click throughout the text area. Verify cursor placement is instant and accurate.
  • Use arrow keys. Verify caret moves natively with no lag.
  • Type 500+ characters continuously. Verify cursor never disappears or blurs.
  • Press Enter multiple times. Verify native paragraph handling.
  • Fill past safe zone boundary. Verify scroll handles overflow smoothly.
  • Edit existing text. Verify insertion point remains stable.

Telemetry Stream (1)

[04:14:33.422] • Sandbox initialized. Single textarea with Lighthouse background.