电子钟：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<span class="hours"></span>:
<span class="minutes"></span>:
<span class="seconds"></span>
<script src="jquery-1.11.1.js"></script>
<script>
function time() {
var date = new Date();
var hour = date.getHours();
var minute = date.getMinutes();
var second = date.getSeconds();
$(".hours").text(hour);
$(".seconds").text(second);
$(".minutes").text(minute);
}
setInterval(time, 1000)
</script>
</body>
</html>
倒计时：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div class="btn">10</div>
<script src="jquery-1.11.1.js"></script>
<script>
var seconds = 10;
function time() {
$(".btn").text(seconds);
seconds--;
if (seconds == 0) {
window.location = "https://www.baidu.com/"
}
}
setInterval(time, 1000)
</script>
</body>
</html>