<html>
<body>
<p>改实例使用了 HTML DOM 向 h1 元素添加 "onmouseenter" 和 "onmouseleave" 事件。</p>
<h1 id="demo">Mouse over me</h1>
<script>
document.getElementById("demo").onmouseenter = function() {mouseEnter()};
document.getElementById("demo").onmouseleave = function() {mouseLeave()};
function mouseEnter() {
document.getElementById("demo").style.color = "red";
}
function mouseLeave() {
document.getElementById("demo").style.color = "black";
}
</script>
</body>
</html>