TabPulse

TabPulse helps you monitor how much load a webpage is putting on your browser by recording approximate CPU activity and JavaScript heap memory usage for the currently active tab. It’s useful for troubleshooting slow sites, catching performance regressions, and understanding which pages are heavier during real browsing.

## Key features
- Live recording for the active tab
- Sampling interval control (250ms–2s)
- CPU% (approximate) based on DevTools performance task time deltas
- JS heap memory: heap used and heap total (MB)
- Simple history view of recent samples in the popup

## How it works
When you press Start, TabPulse temporarily attaches to the active tab using the Chrome DevTools Protocol (`chrome.debugger`) and periodically reads DevTools performance metrics. It then computes:
- CPU% (approx.) from `TaskDuration` change over the selected interval
- Heap used/total from `JSHeapUsedSize` and `JSHeapTotalSize`

## Notes & limitations
- “CPU%” is an approximation, not an operating-system level per-process CPU meter.
- TabPulse **cannot attach to internal browser pages like `chrome://` or other restricted URLs.
- While recording, Chrome may indicate the tab is being debugged (this is required to access DevTools metrics).

## Privacy
TabPulse does not collect or transmit your browsing data.
- *No analytics*
- *No remote servers*
- *No selling/sharing of user data*

Recorded samples are kept locally during the session for display in the popup.

## Permissions explanation
- debugger: required to access DevTools performance metrics for the tab.
- activeTab / tabs: required to identify and attach to the currently active tab.
- storage: used to store recent samples locally during the session.