index.js

let para = document.getElementById('para');  
 let text = document.getElementById('txt');  
 let text2 = document.getElementById('txt2');  
 let btn = document.getElementById('btn');  
 let btn2 = document.getElementById('btn2');  
 window.addEventListener('load', () => {  
  text.placeholder = new Date().getHours();  
  text2.placeholder = new Date().getMinutes();  
 });  
 btn.addEventListener('click', alarm);  
 let x;  
function alarm() {  
  if (text.value && text2.value) {  
   x = setInterval(() => {  
    setAlarm();  
   }, 1000);  
  } 
  else {  
   alert('ENTER THE HRS AND MINS!');  
  }  
}  
function setAlarm() {  
  let d = new Date().toLocaleDateString();  
  let then = new Date(`${d} ${text.value}:${text2.value}`).getTime();  
  let now = new Date().getTime();  
  let distance = then - now;  
  var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));  
  var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));  
  var seconds = Math.floor((distance % (1000 * 60)) / 1000);  
  para.innerHTML = `ALARM IN - ${hours}:${minutes}:${seconds}`;  
  if (distance < 0) {  
   clearInterval(x);  
   para.innerHTML = `IT'S ALARM TIME!`;  
   let audio = new Audio('/audio/alarm.mp3');  
   audio.play();  
   btn2.style.visibility = 'visible';  
   btn2.addEventListener('click', () => {  
    para.innerHTML = ``;  
    audio.pause();  
    btn2.style.visibility = 'hidden';  
    text.value = '';  
    text2.value = '';  
   });  
  }  
}