#import 
#import 
[Exposed=Window, LegacyUnenumerableNamedProperties]
interface HTMLAllCollection {
    readonly attribute unsigned long length;
    getter Element (unsigned long index);
    getter (HTMLCollection or Element)? namedItem([FlyString] DOMString name);
    (HTMLCollection or Element)? item(optional [FlyString] DOMString nameOrIndex);
    // Note: HTMLAllCollection objects have a custom [[Call]] internal method and an [[IsHTMLDDA]] internal slot.
};