#import // https://drafts.csswg.org/resize-observer-1/#resize-observer-interface [Exposed=(Window)] interface ResizeObserver { constructor(ResizeObserverCallback callback); undefined observe(Element target, optional ResizeObserverOptions options = {}); undefined unobserve(Element target); undefined disconnect(); }; enum ResizeObserverBoxOptions { "border-box", "content-box", "device-pixel-content-box" }; dictionary ResizeObserverOptions { ResizeObserverBoxOptions box = "content-box"; }; // https://drafts.csswg.org/resize-observer-1/#resize-observer-callback callback ResizeObserverCallback = undefined (sequence entries, ResizeObserver observer);