If 语句

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>滴答编程(dida100.com)</title>
</head>
<body>

<p>如果时间早于 20:00，会获得问候 "Good day"。</p>
<button onclick="myFunction()">点击这里</button>
<p id="demo"></p>
<script>
function myFunction(){
	var x="";
	var time=new Date().getHours();
	if (time<20){
		x="Good day";
    }
	document.getElementById("demo").innerHTML=x;
}
</script>

</body>
</html>