JSFiddle - React, Tailwind, and code Playground
HTML
<div id="a">Div A</div>
<div>random other elements</div>
<div>random other elements</div>
<div>random other elements</div>
<div id="b">Div B</div>
JavaScript
$('#a').hover(function(){
$('#b').css({'background-color':'#CCC'});
}, function(){
$('#b').css({'background-color':'transparent'});
});