4秒钟倒计时 跳转页面

 <script>
        var count = 4;
        var t;
        function writeTip(){
    
               
document.getElementById("d").innerHTML = "<a href='http://aa.cn'>"+(count--)+"秒</a>";   
            if(count==0){
    
    
                window.clearInterval(t);
                window.location = "http://aa.cn";               
            }
        }


        t = window.setInterval("writeTip()",1000);
    </script>