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<!DOCTYPE html>
<html>
<head>
<style>
div {
  width: 100px;
  height: 100px;
  border: 1px solid black;
  margin: 10px;
  float: left;
  padding: 30px;
  text-align: center;
  background-color: lightgray;
}

p {
  background-color: white;
}
</style>
</head>
<body>

<h3>本例演示了 onmousemove、onmouseleave 与 onmouseout 之间的区别。</h3>

<p>每次鼠标指针移动到 div 元素上时都会发生 onmousemove 事件。</p>
<p>mouseleave 事件仅在鼠标指针移出 div 元素时发生。</p>
<p>onmouseout 事件在鼠标指针移出 div 元素时发生，且当它离开子元素（p 和 span）。</p>

<div onmousemove="myMoveFunction()">
  <p>onmousemove: <br> <span id="demo">请把鼠标悬停在我上面!</span></p>
</div>

<div onmouseenter="myEnterFunction()">
  <p>onmouseenter: <br> <span id="demo2">请把鼠标悬停在我上面!</span></p>
</div>

<div onmouseover="myOverFunction()">
  <p>onmouseover: <br> <span id="demo3">请把鼠标悬停在我上面!</span></p>
</div>

function myMoveFunction() {
  document.getElementById("demo").innerHTML = z+=1;
}

function myEnterFunction() {
  document.getElementById("demo2").innerHTML = x+=1;
}

function myOverFunction() {
  document.getElementById("demo3").innerHTML = y+=1;
}
</script>

</body>
</html>

W3School TIY Editor