function showtime() {
var today;
var hour;
var second;
var minute;
var year;
var month;
var date;
var strDate;
today = new Date();
var n_day = today.getDay();
switch (n_day) {
case 0: {
strDate = "星期日"
}
break;
case 1: {
strDate = "星期一"
}
break;
case 2: {
strDate = "星期二"
}
break;
case 3: {
strDate = "星期三"
}
break;
case 4: {
strDate = "星期四"
}
break;
case 5: {
strDate = "星期五"
}
break;
case 6: {
strDate = "星期六"
}
break;
case 7: {
strDate = "星期日"
}
break;
}
year = today.getYear() - 100 + 2000;
month = today.getMonth() + 1;
date = today.getDate();
hour = today.getHours();
minute = today.getMinutes();
second = today.getSeconds();
if (month < 10)
month = "0" + month;
if (date < 10)
date = "0" + date;
if (hour < 10)
hour = "0" + hour;
if (minute < 10)
minute = "0" + minute;
if (second < 10)
second = "0" + second;
document.getElementById('clock').innerHTML = year + "年" + month + "月"
+ date + "日 " + strDate + " " + hour + ":" + minute + ":" + second;
setTimeout("showtime();", 1000);
}
<body onLoad="showtime()">
<span style="float:left">
<span>当前时间</span>
<span id="clock"></span>
</span>
</body>
