javascript计时器

var c=0;  
var t;
function timedCount() 
{
	hour = parseInt(c / 3600);// 小时
	min = parseInt(c / 60);// 分钟 
	if(min>=60){ 
		min=min%60; 
	} 
lastsecs = c % 60; 
//转为00:00:00格式
lastsecs = lastsecs<10?(‘0‘+lastsecs):lastsecs;
min = min<10?(‘0‘+min):min;
hour = hour<10?(‘0‘+hour):hour; 
$("#time").html(" : "+hour + ":" + min + ":" + lastsecs);  
c=c+1;
t=setTimeout("timedCount()",1000);
}
function stopCount()
{
clearTimeout(t);       
}
function clearAll(){
 c=0;
 clearTimeout(t);    
}

<div id="time"></div>