var tick;  
function stop() {  
clearTimeout(tick);  
}  
function nowtime()  
    {  
        var ut=new Date();  
        var h,m,s;  
        var time="     ";  
        h=ut.getHours();  
        m=ut.getMinutes();  
        s=ut.getSeconds();  
        if(s<=9) s="0"+s;  
        if(m<=9) m="0"+m;  
        if(h<=9) h="0"+h;  
        time+=h+":"+m+":"+s;  
        document.rclock.rtime.value=time;  
        tick=setTimeout("nowtime()",1000);  
}