JS控制按钮10秒钟后可用的方法

<script language="javascript">function start(){  document.getElementById("Button1").disabled = true;  document.getElementById("Button1").value = 10;  window.setTimeout("tick()",1000);}function tick(){  var time = new Number(document.getElementById("Button1").value);  if(time>0)  {    document.getElementById("Button1").value = time-1;    window.setTimeout("tick()",1000);  }  else  {    document.getElementById("Button1").disabled = false;    document.getElementById("Button1").value = "保存";  }}</script><form><INPUT TYPE="button" NAME="Button1" id="Button1"></form><script language=javascript> start();</script>