禁止刷新頁面倒計時

第一種：

<SCRIPT LANGUAGE="JavaScript">
    var intDiff;
    function gradeId(gradeId){
    	if(window.name=='' || window.name == '-1' || isNaN(window.name)){//禁止頁面刷新
            if(gradeId==8||gradeId==9){
                intDiff = parseInt(60*40);
            }else{
                intDiff = parseInt(60*30);//倒計時總秒數量
            }
    	}else{
            intDiff = window.name;
    	}
    }
    function CountDown(){
    	if(intDiff>=0){
        	hours = Math.floor(intDiff/3600);
        	minutes = Math.floor((intDiff-hours*3600)/60);
        	seconds = Math.floor(intDiff%60);
        	msg = "距離考試結束還有"+minutes+"分"+seconds+"秒";
        	document.all["timer"].innerHTML = msg;
        	if(intDiff == 5*60) alert('注意，還有5分鐘!');
        	--intDiff;
        	window.name = intDiff;
        	console.log(intDiff);
    	}else{
    		clearInterval(timer);
    		alert("考試時間到")
    	}
    }
    //js控制定時執行,每隔一段時間定時執行
    //後臺查詢執行請求 1s 
    timer = setInterval("CountDown()",1000);
</SCRIPT>
<div id="timer" style="color:red"></div>

 

//js控制延時跳轉
//延遲跳轉 20min
setTimeout('ys_time_out()', 1000*60*20);