Poor TBT (Total Blocking Time) Test Page

This page runs a synchronous blocking loop on mount to trigger the slow_page issue via high TBT.

TBT measures the total time the main thread was blocked by long tasks during page load. Good TBT is 200ms or less.

Main thread is blocked...

What's wrong?

• Heavy synchronous JavaScript blocks the main thread on load
• Creates a long task (>50ms) detected by PerformanceObserver
• TBT exceeds the 200ms threshold
• No web workers or task splitting used

TBT Thresholds:

• Good: ≤ 200ms
• Needs Improvement: 200-600ms
• Poor: > 600ms