in this excercise i create a counter that has a number display and 2 button to lower and increase number. i assign number to parseInt(num) to convert num object to number. i use alert to check type of number. typeof(number) return number but number return NaN. please someone explain.[edit]reading comment, i was able to solve the problem. i have upadated the solution
var low = document.getElementById("low")
var add = document.getElementById("add")
low.addEventListener("click", function () {
var num = document.getElementById("num")
var number = parseInt(num.innerText)
num.innerHTML = number - 1
})
add.addEventListener("click", function () {
var num = document.getElementById("num")
var number = parseInt(num.innerText)
num.innerHTML = number + 1
})<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<!-- <link rel="stylesheet" href="style.css"> -->
</head>
<body>
<div class="container">
<h1>counter</h1>
<h1 id="num">0</h1>
<div class="btn">
<button id="low">lower count</button>
<button id="add">add count</button>
</div>
</div>
<script src="js.js"></script>
</body>
</html>You are trying to parseInt(num) but num is DOM element - not number. You want its content. You can get it with .innerText.
const num = document.getElementById("num")
console.log(num);
console.log(parseInt(num));
console.log(parseInt(num.innerText));<h1 id="num">0</h1>