$(function () {
setInterval(function () {
var time = $("#time").text();
time = parseInt(time);
time--;
if (time >0) {
$("#time").text(time);
} else {
window.location = $("#url").attr("href");
}
}, 1000);
});

<script type="text/javascript">
window.onload = function () {
setTimeout(changeTime, 1000);
}
function changeTime() {
var time = document.getElementById("time").innerHTML;
time = parseInt(time);
time--;
if (time <= 0) {
var url = document.getElementById("url").href;
window.location = url;
} else {
document.getElementById("time").innerHTML= time;
setTimeout(changeTime, 1000);
}
}
</script>

<span style="font-size: 18px; color: Red" id="time">5</span>秒鐘以后跳轉到 <a href="<%=this.url %>"