代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>demo</title>
</head>
<script>
function startTime() {
var today = new Date();
var h = today.getHours();
var m = today.getMinutes();
var s = today.getSeconds();
//美化前面+1
m = checkTime(m);
s = checkTime(s);
document.getElementById('txt').innerHTML = h + ":" + m + ":" + s;
t = setTimeout('startTime()', 500);
}
//当数字小于10的时候。前面+1
function checkTime(i) {
if (i < 10) {
i = "0" + i;
}
return i;
}
</script>
<body onload="startTime()">
<h1>显示一个钟表</h1>
<div id="txt"></div>
</body>
</html>效果：
