The mouseover event is fired when a pointing device is moved onto the element that has the listener attached or onto one of its children.
MouseEvent| 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 following example illustrates the difference between mouseover and mouseenter events.
<ul id="test">
  <li>item 1</li>
  <li>item 2</li>
  <li>item 3</li>
</ul>
<script>
  var test = document.getElementById("test");
  
  
  // this handler will be executed only once when the cursor moves over the unordered list
  test.addEventListener("mouseenter", function( event ) {   
    // highlight the mouseenter target
    event.target.style.color = "purple";
    // reset the color after a short delay
    setTimeout(function() {
      event.target.style.color = "";
    }, 500);
  }, false);
  
  
  // this handler will be executed every time the cursor is moved over a different list item
  test.addEventListener("mouseover", function( event ) {   
    // highlight the mouseover target
    event.target.style.color = "orange";
    // reset the color after a short delay
    setTimeout(function() {
      event.target.style.color = "";
    }, 500);
  }, false);
</script>
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| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Edge | Opera | Safari | 
|---|---|---|---|---|---|---|
| Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | 
| On disabled form elements | (Yes)[1] | 44.0 (44.0)[2] | (Yes) | No support | (Yes)[1] | ? | 
| Feature | Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile | 
|---|---|---|---|---|---|---|
| Basic support | ? | (Yes) | ? | ? | ? | ? | 
| On disabled form elements | ? | No support | ? | ? | ? | ? | 
[1] Only works for <textarea> elements and some <input> element types.
[2] Implemented in bug 218093.
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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
    https://developer.mozilla.org/en-US/docs/Web/Events/mouseover