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.
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
Important: Do not use this non-standard and obsolete event. Instead, you should always use the standard
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.
BCD tables only load in the browser
- Gecko's legacy line or page scroll event:
- Non-Gecko browsers' legacy mouse wheel event:
- Standardized wheel event: