JSFiddle - React, Tailwind, and code Playground

HTML

<div id="sub1" class="menu">
    1
</div>
<br/>
<div id="sub2" class="menu">
    2
</div>
<br/>
<div class='sub1-1'>sub1</div>
<div class='sub2-1'>sub2</div>

CSS

.menu{
   background-color: yellow;
   width:200px;
}

JavaScript

$('div[class^=sub]').hide();
$('.menu').mouseover(function(){
    var id = $(this).attr('id');
    $('div[class^=sub]').hide();
    $('.'+id+'-1').show();
});