Js倒计时代码，当鼠标离开页面与回到页面会自动停止与开始_时间日期

<title>根据鼠标判断时间：Js倒计时</title> <input type="button" id="downloadbtn" class="meng1an" onclick='if(timeout>0) {alert("停止计时");return false;}document.location="#"; this.disabled=true;'> <script type="text/javascript"> <!-- var timeCount var timeout='10'; function countdown() { if (timeout <= 0) { document.getElementById("downloadbtn").value = '时间到'; if(document.getElementById("downloadfile"))document.getElementById("downloadfile").style.display = ''; } if (timeout > 0) { document.getElementById("downloadbtn").value = '还有 '+timeout+' 秒'; timeCount = setTimeout('countdown()',1000); } timeout--; } countdown(); document.onmouseover= function(){clearTimeout(timeCount);countdown();} document.onmouseout= function(){clearTimeout(timeCount);} --> </script>
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]