<html>
<body>
<p>点击按钮根据时间输出问候语。</p>
<button onclick="myFunction()">点我</button>
<p id="demo"></p>
<script>
function myFunction() {
var time = new Date().getHours();
var greeting;
if (time < 10) {
greeting = "Good morning";
} else if (time < 20) {
greeting = "Good day";
} else {
greeting ="Good evening";
}
document.getElementById("demo").innerHTML = greeting;
}
</script>
</body>
</html>