n秒后自动跳转JS

<script type="text/javascript">
<!--
var time = 0;
var forward_url = "";//某页网址
function forward_to(){
    time ++;
    if(time == 5){
        document.location.href = forward_url;
    }
    document.getElementById("message").innerHTML = (3 - time) + "秒后自动跳转到某页";
}
window.setInterval("forward_to()",1000);
-->
</script>