anchor.diff:    /// See <https://developer.mozilla.org/en-US/docs/Web/API/AnimationEvent/elapsedTime>
     external num get elapsedTime;
   
  -  /// Is a DOMString, starting with '::', containing the name of the pseudo-element the animation runs on.
  +  /// A [String], starting with '::', containing the name of the pseudo-element the animation runs on.
     ///
     /// If the animation doesn't run on a pseudo-element but on the element, an empty string: ''.
     ///
  
positive.code:   /// Use `createSyntheticWheelEvent` instead.
    external factory SyntheticWheelEvent._();
  
    /// Represents the horizontal scroll amount.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/WheelEvent/deltaX>
    external num get deltaX;
  
    /// Represents the unit of the `delta*` values' scroll amount.
    ///
    /// Permitted values are:
    /// - WheelEvent.DOM_DELTA_PIXEL
  
negative.code:   /// Use `createSyntheticKeyboardEvent` instead.
    external factory SyntheticKeyboardEvent._();
  
    /// Whether the `Alt` (`Option` or `⌥` on OS X) key was active when this event was generated.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/altKey>
    external bool get altKey;
  
    /// The character value of the key.
    ///
    /// If the key corresponds to a printable character, this value is a non-empty Unicode string containing that character.
    /// If the key doesn't have a printable representation, this is an empty string.
    external String get char;
  
    /// Whether the `Ctrl` key was active when this was generated.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/ctrlKey>
    external bool get ctrlKey;
  
    /// A locale string indicating the locale the keyboard is configured for.
    ///
    /// This may be the empty string if the browser or device doesn't know the keyboard's locale.
    external String get locale;
  
    /// The location of the key on the keyboard or other input device.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/location>
    external num get location;
  
    /// The key value of the key represented by this event.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/key>
    external String get key;
  
    /// Whether the `Meta` key (on Mac keyboards, the `⌘ Command key`; on Windows keyboards, the Windows key (`⊞`))
    /// was active when the key event was generated.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/metaKey>
    external bool get metaKey;
  
    /// Whether the key is being held down such that it is automatically repeating.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/repeat>
    external bool get repeat;
  
    /// Whether the `Shift` key was active when the this event was generated.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/shiftKey>
    external bool get shiftKey;
  
    /// A system and implementation dependent numerical code identifying the unmodified
    /// value of the pressed key.
    ///
    /// See <https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/keyCode>
    external num get keyCode;
  
    /// The Unicode reference number of the key; this attribute is used only by the `keypress` event.
    ///
    /// For keys whose `char` attribute contains multiple characters, this is the Unicode value of the first character in
    /// that attribute. In Firefox 26 this returns codes for printable characters.
  