Sum div data to field value

by borisjavier

HTML

<div id="demo" align="center"  data-value="1">1</div>
<input type="number" id="n1" onchange="calc()">

JavaScript

var val = document.getElementById('demo').getAttribute('data-value');
//alert(val);
const n1 = document.getElementById('n1');


//

function calc() {
if(n1 != "0") {
demo.innerHTML = Number(val) + Number(n1.value);
} 
}

//n1.addEventListener('keyup', calc);