#import 
[MissingValueDefault=auto, InvalidValueDefault=auto]
enum ClosedByAttribute {
    "any",
    "closerequest",
    "none"
};
// https://html.spec.whatwg.org/multipage/semantics.html#htmldialogelement
[Exposed=Window]
interface HTMLDialogElement : HTMLElement {
    [HTMLConstructor] constructor();
    [CEReactions, Reflect] attribute boolean open;
    attribute DOMString returnValue;
    [CEReactions, Reflect=closedby, Enumerated=ClosedByAttribute] attribute DOMString closedBy;
    [CEReactions] undefined show();
    [CEReactions] undefined showModal();
    [CEReactions] undefined close(optional DOMString returnValue);
    [CEReactions] undefined requestClose(optional DOMString returnValue);
};