JSFiddle - React, Tailwind, and code Playground

HTML

<div id="test1">сюда наводим</div> 
<div id="test2">тут меняется</div>

CSS

#test1, #test2{height:100px; border:1px dotted silver;}

JavaScript

$("#test1").hover(
    function(){
        $("#test2").css("background","blue");
    },
    function(){
        $("#test2").css("background","green");
    }
);