JSFiddle - React, Tailwind, and code Playground

by Aaron Zhang

HTML

<input type="text" id="number">
<button id="btnReverse">reverse</button>

JavaScript

function reverseNumber(n){
    if(typeof n!= "number" || !isFinite(n)){
        throw "Incorrect type of input"
    }
    return parseFloat(n.toString().split("").reverse().join(""));
}
function calculate(){
    var n = parseFloat(document.getElementById('number').value);
    if(n){
        document.getElementById('number').value = reverseNumber(n);   
    }
}
$('#btnReverse').click(calculate);