<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.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>

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>

<p>点击这个按钮，获得基于时间的问候。</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";
     }
    else{
         x="Good evening";
     }
    document.getElementById("demo").innerHTML=x;
}
</script>

</body>
</html>

<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>

<script type="text/javascript">
var d = new Date();
var time = d.getHours();
if (time<10)
{
    document.write("<b>早上好</b>");
}
else if (time>=10 && time<16)
{
    document.write("<b>今天好</b>");
}
else
{
    document.write("<b>晚上好!</b>");
}
</script>
<p>
这个例子演示了 if..else if...else 语句。
</p>

</body>
</html>

<!DOCTYPE html>
<html>
<head> 
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> 
</head>
<body>

<p id="demo"></p>
<script>
var r=Math.random();
var x=document.getElementById("demo")
if (r>0.5){
    x.innerHTML="<a href='http://www.runoob.com'>访问菜鸟教程</a>";
}
else{
    x.innerHTML="<a href='http://wwf.org'>Visit WWF</a>";
}
</script>

</body>
</html>