JScript 页面倒计时

 <script type="text/javascript" language="javascript">
            var secs = 10;
            var wait = secs * 1000;
            var agreetext="ok";
            document.form1.Button1.value = agreetext+"(" + secs + ") ";
            document.form1.Button1.disabled = true;
            for(i = 1; i <= secs; i++) {
             window.setTimeout("update(" + i + ")", i * 1000);}window.setTimeout("timer()", wait);
            function update(num, value) {
             if(num == (wait/1000)) {
             document.form1.Button1.value = agreetext;
             } else {
             printnr = (wait / 1000)–num;
             document.form1.Button1.value = agreetext+"(" + printnr + ") ";
             }
            }
            function timer() {
             document.form1.Button1.disabled = false;
             document.form1.Button1.value = agreetext;
            }
      </script>