amrutha.js

var seconds = 0;
var mins = 0 ;
var hours =0
const lengthOfTime=3;

function updateTimer() {
    seconds = seconds+1;
    if(seconds>=lengthOfTime){
        seconds=0;
        mins = mins+1;
        if(mins>=lengthOfTime){                        
            hours = hours+1;            
            mins=0;  
            if(hours>=24){
                hours = 0;
                mins=0;
                seconds=0;                        
            }          
        }        
    }    
    document.getElementById("seconds").innerHTML=seconds;
    document.getElementById("minutes").innerHTML=mins;
    document.getElementById("hours").innerHTML=hours;
}

setInterval(updateTimer,1000);