index.js

let score = 0
let time = 20
let mouse = document.getElementById('mouse')
let timer = document.getElementById('timer')
let scoreBoard = document.getElementById('score_container')
let resultPage = document.getElementById('resultPage')
let soundeffect = document.getElementById('soundEffect')


function fadeOutStart(str){
  document.getElementById(str).parentElement.style.opacity = '0'
}


function gameFunction(){
  if (mouse.style.opacity == 0 && time > 0) {
    mouse.style.opacity = 1
    mouse.style.zIndex = 1
    let leftPosition = Math.floor(Math.random()*(50)) + 2
    let topPosition = Math.floor(Math.random()*(40)) + 40
    mouse.style.left = `${leftPosition}%`
    mouse.style.top = `${topPosition}%`
  } else {
    mouse.style.opacity= '0'
    mouse.style.zIndex= '0'
  }
}


function start(){
  if(time > 0){
    setInterval(startTimer,1500)
    setInterval(gameFunction,1000)
    timer.style.opacity= '1'
    timer.style.zIndex= '1'
    scoreBoard.style.opacity= '1'
    scoreBoard.style.zIndex= '1'  
  } 
}


function startTimer(){
  time--
  timer.innerHTML = `${time}`
  if(time === 0){
    stop()
  }
}

function stop(){
  timer.style.opacity= '0'
  timer.style.zIndex= '0'
  scoreBoard.style.opacity= '0'
  scoreBoard.style.zIndex= '0'
  mouse.style.opacity= '0'
  mouse.style.zIndex= '0'
  resultPage.style.opacity='1'
  result()
}

function result(){
  if(score <= 20){
    document.getElementById('statusMisi').innerHTML = `MISSION INCOMPLATED`
    document.getElementById('paragraph').innerHTML = `you have failed to save the kingdom, 
    the residents are waiting for you to fight back. 
    let's rejoin the royal army to save the kingdom and celebrate our victory`
    document.getElementById('status').innerHTML = `YOU ARE NOOB`
    document.getElementById('back').style.top = '90%';
  }
}

mouse.addEventListener("click", counterScore)

function counterScore(){
  if(time >= 1){
    score++
    mouse.style.opacity = 0
    document.getElementById('score').innerHTML = `${score}`
  }
}

mouse.addEventListener("click", playAudio)

function playAudio() {
  soundeffect.play();
}