Custom Element Counter 作者： Magoyor

This add‑on lets you count DOM elements on any webpage using a CSS selector or an XPath expression.

Features:
- Count elements with CSS selector or XPath
- Auto‑refresh in the background with adjustable interval
- Toolbar badge shows the count (0–999, then 1k‑99k, then ∞)
- Optional Shadow DOM traversal (needed for modern web components)
- Save up to 5 presets for quick access
- Works on all websites – no data collection, no external requests

⚠️ No maintenance: This add‑on was created for personal use and is published as‑is. I do not provide updates, bug fixes, or support. Use at your own risk.

Source code: https://github.com/Magoyor/custom-element-counter-addon