Performance check
DOM size
Counts the HTML elements in the document as served.
- Category
- Performance
- Importance
- Medium importance
- Check id
- dom-size
How the result is decided
- Pass1,500 elements or fewer.
- WarningUp to 3,000.
- FailMore than 3,000.
Why it matters
A large DOM uses more memory and makes styling, layout and scripts slower, especially on phones.
How to fix it
Simplify deeply nested markup, paginate or virtualize long lists, and don’t render hidden content (menus, tabs, modals) until it’s needed.
After the fix, open the page’s report and choose Run again to confirm it passes.