JSFiddle - React, Tailwind, and code Playground

HTML

<style>
    #content {
        display: block;
        width: 200px;
        height: 200px;
        background-color: yellow;
    }
</style>



<div id="content">
    dodododododo.....
</div>

<script>
var content = document.getElementById('content');

content.addEventListener('mouseenter', function (e) {
    console.log('enter');
});

content.addEventListener('mouseleave', function (e) {
    console.log('leave');
});
</script>

JavaScript

var one = "1";
var two = "2";

one = parseInt(one);
two = parseInt(two);

console.log(one + two);