倒计时按钮

 请按钮倒计时多少时间后才有效。

 

<form name="test" action="" method="post">

<input type="submit" name="Submit" value="获取答案">
            <script language="javascript">
            document.test.Submit.disabled = true;
            var speed = 1000; //速度
            var wait = 600; //停留时间
            function updateinfo(){
              if(wait == 0){
                document.test.Submit.value = "获取答案";
                document.test.Submit.disabled = false;
              }
              else{
                document.test.Submit.value = "请先思考"+wait;
                wait--;
                window.setTimeout("updateinfo()",speed);
              }
            }
            updateinfo();
            </script>