<html><body><h1>Window 对象</h1><h2>setTimeout() 方法</h2><p>请单击按钮。等待 3 秒可收到提醒："Hello!"。</p><button onclick="myFunction()">试一试</button><script>let timeout;function myFunction() { timeout = setTimeout(alertFunc, 3000);}function alertFunc() { alert("Hello!");}</script></body></html>