tryjsref_onmouseenter_addeventlistener 在线代码实例

 <p>该实例使用了 addEventListener() 方法向 h1 元素添加 "mouseenter" 和 "mouseleave" 事件。</p>

<h1 id="demo">Mouse over me</h1>
<script>
document.getElementById("demo").addEventListener("mouseenter", mouseEnter);
document.getElementById("demo").addEventListener("mouseleave", mouseLeave);
function mouseEnter() {
    document.getElementById("demo").style.color = "red";
}
function mouseLeave() {
    document.getElementById("demo").style.color = "black";
}
</script>