Understanding Browser Automation: Accessibility Trees vs DOM Parsing

Modern browser automation has evolved beyond simple DOM manipulation.

The Accessibility Tree Advantage

The accessibility tree is the same structured representation that screen readers use. Instead of fragile CSS selectors, you target elements by semantic role and label.

Framework Comparison

Playwright leads with cross-browser support, auto-waiting, and accessibility tree API. Selenium remains relevant for legacy but lacks modern features.

Best Practices

1. Query the accessibility tree first
2. Re-snapshot after mutations
3. Use network idle waits
4. Verify every action

The combination of structured data + visual fallback creates agents that handle any web interface.