Tab Focus Bypass

Detection approach

A link with target='_blank' was clicked, but neither window.blur nor document.visibilityState='hidden' fired on the original tab. Puppeteer opens tabs in the background while keeping script focus on the original page — this combined check catches that evasion.

How this helps detect bots

This signal is assessed with other independent session, browser, and network evidence. A single anomaly is a lead, not a verdict; corroborating anomalies make automated traffic more likely.

Legitimate traffic to consider

Secure custom extensions managing focus layers, or pop-up management configurations.