The mouseenter event is fired at an Element when a pointing device (usually a mouse) is initially moved so that its hotspot is within the element at which the event was fired.

Bubbles No
Cancelable No
Interface MouseEvent
Event handler property onmouseenter

Usage notes

Though similar to mouseover, mouseenter differs in that it doesn't bubble and it isn't sent to any descendants when the pointer is moved from one of its descendants' physical space to its own physical space.

mouseenter.png
One mouseenter event is sent to each element of the hierarchy when entering them. Here 4 events are sent to the four elements of the hierarchy when the pointer reaches the text.
mouseover.png
A single mouseover event is sent to the deepest element of the DOM tree, then it bubbles up the hierarchy until it is canceled by a handler or reaches the root.

With deep hierarchies, the number of mouseenter events sent can be quite huge and cause significant performance problems. In such cases, it is better to listen for mouseover events.

Combined with the corresponding mouseleave (which is fired at the element when the mouse exits its content area), the mouseenter event acts in a very similar way to the CSS :hover pseudo-class.

Examples

The mouseover documentation has an example illustrating the difference between mouseover and mouseenter.

mouseenter

The following trivial example uses the mouseenter event to change the border on the div when the mouse enters the space alloted to it. It then adds an item to the list with the number of the mouseenter or mouseleave event.

HTML

<div id='mouseTarget'>
 <ul id="unorderedList">
  <li>No events yet!</li>
 </ul>
</div>

CSS

Styling the div to make it more visible.

#mouseTarget {
  box-sizing: border-box;
  width:15rem;
  border:1px solid #333;
}

JavaScript

var enterEventCount = 0;
var leaveEventCount = 0;
const mouseTarget = document.getElementById('mouseTarget');
const unorderedList = document.getElementById('unorderedList');

mouseTarget.addEventListener('mouseenter', e => {
  mouseTarget.style.border = '5px dotted orange';
  enterEventCount++;
  addListItem('This is mouseenter event ' + enterEventCount + '.');
});

mouseTarget.addEventListener('mouseleave', e => {
  mouseTarget.style.border = '1px solid #333';
  leaveEventCount++;
  addListItem('This is mouseleave event ' + leaveEventCount + '.');
});

function addListItem(text) {
  // Create a new text node using the supplied text
  var newTextNode = document.createTextNode(text);

  // Create a new li element
  var newListItem = document.createElement("li");

  // Add the text node to the li element
  newListItem.appendChild(newTextNode);

  // Add the newly created list item to list
  unorderedList.appendChild(newListItem);  
}

Result

Specifications

Specification Status
UI Events
The definition of 'mouseenter' in that specification.
Working Draft
Document Object Model (DOM) Level 3 Events Specification
The definition of 'mouseenter' in that specification.
Obsolete

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
mouseenter eventChrome Full support 30Edge Full support YesFirefox Full support 10IE Full support 5.5Opera Full support 17Safari Full support YesWebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support 10Opera Android Full support 18Safari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support

See also