HTML 中 - 在线编辑器

          <p>该实例演示了如何向 h1 元素添加 "onmouseenter" 和 "onmouseleave" 事件。</p>
<h1 id="demo" onmouseenter="mouseEnter()" onmouseleave="mouseLeave()">鼠标移到我这</h1>
<script>
  function mouseEnter() {
    document.getElementById("demo").style.color = "red";
  }

  function mouseLeave() {
    document.getElementById("demo").style.color = "black";
  }
</script>
        