// CATEGORY · knowledge/browser/

Browser Engine

DOM, CSS, layout, iframes, navigation, and engine-level behavior.

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Dev story — work in progress

These posts are engineering notes from building Koko. They capture what we believed at the time — some lessons aged well, some did not. Treat them as a lab notebook, not official docs. Corrections and better ideas are welcome.

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All Bug Stories1 Captcha & Detection1 Performance1 SDK1 Browser Engine1

Browser Enginebrowser/iframe/owner-frame-cross-document-styles.md

Owner Frame Resolution for Cross-Document Style Operations

CreepJS runs many CSS probes inside a nested phantom but calls unqualified from the main window realm. Koko routed style operations through the caller's instead of the element owner's , so custom properties and stylesheets landed on the parent document while reads targeted the iframe . Fixing usag

June 30, 2026

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