interface Event {

    constructor(DOMString type, optional EventInit eventInitDict = {});

    readonly attribute DOMString type;
    readonly attribute EventTarget? target;
    readonly attribute EventTarget? srcTarget;
    readonly attribute EventTarget? currentTarget;

    readonly attribute unsigned short eventPhase;

    undefined stopPropagation();
    attribute boolean cancelBubble;
    undefined stopImmediatePropagation();

    readonly attribute boolean bubbles;
    readonly attribute boolean cancelable;
    attribute boolean returnValue;
    undefined preventDefault();
    readonly attribute boolean defaultPrevented;
    readonly attribute boolean composed;

    readonly attribute boolean isTrusted;

    undefined initEvent(DOMString type, optional boolean bubbles = false, optional boolean cancelable = false);

};

dictionary EventInit {
    boolean bubbles = false;
    boolean cancelable = false;
    boolean composed = false;
};