404页面自动跳转javascript

5秒后自动跳到系统<a href="login.aspx">登录界面</a>...还剩<span id="time" style="font-weight:bold;color: blue">5</span>秒！

 

<script type="text/javascript">
           var i = 5;
           window.onload = function page_cg() {
               document.getElementById("time").innerText = i;
               i--;
               if (i == 0) {
                   window.location.href("login.aspx");
               }
               setTimeout(page_cg, 1000);
           }
    </script>