JSFiddle - React, Tailwind, and code Playground

HTML

<div id="b1" style="display: block;">
    <div>1</div>
    <div>2</div>
    <div>3</div>
</div>
<div id="b2" style="display: none;">
    <div>4</div>
    <div>5</div>
    <div>6</div>
</div>

JavaScript

$(function() {
    $('#b1').mouseenter(function(){
        $(this).css('display','none');
        $('#b2').css('display','block');
    });
    $('#b2').mouseleave(function(){
        $(this).css('display','none');
        $('#b1').css('display','block');
    });
})