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The mouseenter event is fired when a pointing device (usually a mouse) is moved over the element that has the listener attached.

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

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.
One 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 amount 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 behavior of its symmetrical event, mouseleave, the mouseenter DOM Event acts in a very similar way to the CSS :hover pseudo-class.

General info

Default Action


Property Type Description
target Read only EventTarget The event target (the topmost target in the DOM tree).
type Read only DOMString The type of event.
bubbles Read only Boolean Whether the event normally bubbles or not
cancelable Read only Boolean Whether the event is cancellable or not?
view Read only WindowProxy document.defaultView (window of the document)
detail Read only long (float) 0.
currentTarget Read only EventTarget The node that had the event listener attached.
relatedTarget Read only EventTarget For mouseover, mouseout, mouseenter and mouseleave events: the target of the complementary event (the mouseleave target in the case of a mouseenter event). null otherwise.
screenX Read only long The X coordinate of the mouse pointer in global (screen) coordinates.
screenY Read only long The Y coordinate of the mouse pointer in global (screen) coordinates.
clientX Read only long The X coordinate of the mouse pointer in local (DOM content) coordinates.
clientY Read only long The Y coordinate of the mouse pointer in local (DOM content) coordinates.
button Read only unsigned short This is always 0 as no button presses trigger this event (mouse movement does).
buttons Read only unsigned short The buttons depressed when the mouse event was fired: Left button=1, Right button=2, Middle (wheel) button=4, 4th button (typically, "Browser Back" button)=8, 5th button (typically, "Browser Forward" button)=16. If two or more buttons are depressed, returns the logical sum of the values. E.g., if Left button and Right button are depressed, returns 3 (=1 | 2). More info.
mozPressure Read only float The amount of pressure applied to a touch or tabdevice when generating the event; this value ranges between 0.0 (minimum pressure) and 1.0 (maximum pressure).
ctrlKey Read only boolean true if the control key was down when the event was fired. false otherwise.
shiftKey Read only boolean true if the shift key was down when the event was fired. false otherwise.
altKey Read only boolean true if the alt key was down when the event was fired. false otherwise.
metaKey Read only boolean true if the meta key was down when the event was fired. false otherwise.


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

The following example illustrates how to use mouseover to simulate the principle of event delegation for the mouseenter event.

<ul id="test">
    <ul class="enter-sensitive">
      <li>item 1-1</li>
      <li>item 1-2</li>
    <ul class="enter-sensitive">
      <li>item 2-1</li>
      <li>item 2-2</li>

  var delegationSelector = ".enter-sensitive";

  document.getElementById("test").addEventListener("mouseover", function( event ) {
    var target =,
        related = event.relatedTarget,

    // search for a parent node matching the delegation selector
    while ( target && target != document && !( match = matches( target, delegationSelector ) ) ) {
        target = target.parentNode;

    // exit if no matching node has been found
    if ( !match ) { return; }

    // loop through the parent of the related target to make sure that it's not a child of the target
    while ( related && related != target && related != document ) {
        related = related.parentNode;

    // exit if this is the case
    if ( related == target ) { return; }

    // the "delegated mouseenter" handler can now be executed
    // change the color of the text = "orange";
    // reset the color after a small amount of time
    setTimeout(function() { = "";
    }, 500);

  }, false);

  // function used to check if a DOM element matches a given selector
  // the following code can be replaced by this IE8 compatible function:
  function matches( elem, selector ){
    // the matchesSelector is prefixed in most (if not all) browsers
    return elem.matchesSelector( selector );

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support 30[1] (Yes) 10[2] 5.5 (Yes)
No support 15.0
On disabled form elements No support No support 44.0 (44.0)[4] No support No support ?
Feature Android Chrome for Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? ? (Yes) ? ? ? ?
On disabled form elements ? ? No support ? ? ? ?

[1] Implemented in bug 236215.

[2] Implemented in bug 432698.

[3] Safari 7 fires the event in many situations where it's not allowed to, making the whole event useless. See bug 470258 for the description of the bug (it existed in old Chrome versions as well). Safari 8 has correct behavior

[4] Implemented in bug 218093.

See also


 最終更新者: vapier,