<html><body><p>此示例使用 HTML DOM 将“onmouseenter”和“onmouseleave”事件分配给 h1 元素。</p><h1 id="demo">鼠标悬停在我身上</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>