FrontendHaltBrowser internals·Intermediate·Conceptual·1 min read
What is forced synchronous layout?
Short interview answer
JavaScript mutates styles or DOM and then reads layout-dependent geometry, forcing the browser to calculate pending style and layout immediately. Repeating reads and writes in a loop causes layout thrashing.
Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.