Document: wheel event
The wheel
event fires when the user rotates a wheel button on a pointing device (typically a mouse).
Bubbles | Yes |
---|---|
Cancelable | Yes |
Interface | WheelEvent |
Event handler property | GlobalEventHandlers.onwheel |
This event replaces the non-standard deprecated mousewheel
event.
Note: Don't confuse the wheel
event with the scroll
event. The default action of a wheel
event is implementation-specific, and doesn't necessarily dispatch a scroll
event. Even when it does, the delta*
values in the wheel
event don't necessarily reflect the content's scrolling direction. Therefore, do not rely on the wheel
event's delta*
properties to get the scrolling direction. Instead, detect value changes of scrollLeft
and scrollTop
in the scroll
event.
Examples
Scaling an element via the wheel
This example shows how to scale an element using the mouse (or other pointing device) wheel.
<div>Scale me with your mouse wheel.</div>
body {
min-height: 100vh;
margin: 0;
display: flex;
align-items: center;
justify-content: center;
}
div {
width: 105px;
height: 105px;
background: #cdf;
padding: 5px;
}
function zoom(event) {
event.preventDefault();
if (event.deltaY < 0) {
// Zoom in
scale *= event.deltaY * -2;
}
else {
// Zoom out
scale /= event.deltaY * 2;
}
// Restrict scale
scale = Math.min(Math.max(.125, scale), 4);
// Apply scale transform
el.style.transform = `scale(${scale})`;
}
let scale = 1;
const el = document.querySelector('div');
document.onwheel = zoom;
addEventListener equivalent
The event handler can also be set up using the addEventListener()
method:
document.addEventListener('wheel', zoom);
Specifications
Specification |
---|
UI Events # event-type-wheel |
Browser compatibility
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