Element: MozMousePixelScroll event

Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The Firefox-only, non-standard, and obsolete MozMousePixelScroll event is fired at an Element asynchronously when a mouse wheel or similar device is operated. It's represented by the MouseScrollEvent interface.

Note: Do not use this non-standard and obsolete event. Instead, you should always use the standard wheel event.


Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("MozMousePixelScroll", (event) => {});

onMozMousePixelScroll = (event) => {};

Event type

Getting the distance scrolled

The event's detail property indicates the scroll distance in terms of lines, with negative values indicating the scrolling movement is either toward the bottom or toward the right, and positive values indicating scrolling to the top or left.

If the platform's native mouse wheel events indicate the scroll distance in terms of lines or pages, the value of detail is computed using that value and the line height or page width/height of the nearest ancestor scrollable element that contains the target element.

Note: On macOS, the scroll distance (and therefore the value of detail) is computed based on the accelerated scroll distance.

The value of detail is never 0 if the events are legitimate.

Browser compatibility

BCD tables only load in the browser

See also

  • MouseScrollEvent
  • Gecko's legacy line or page scroll event: DOMMouseScroll
  • Non-Gecko browsers' legacy mouse wheel event: mousewheel
  • Standardized wheel event: wheel