JSFiddle - React, Tailwind, and code Playground

HTML

<!-- jQuery.proxy() Example -->
<!-- blog.kevinchisholm.com -->

<div id="container">
    <div class="item left">
        click me to make the other one red.
    </div>
    <div class="item right">
        click me to make the other one blue.
    </div>
</div>

CSS

#container{
    width:80%;
    margin:20px auto;
    text-align:center;
}
.item:hover{cursor:pointer;}
.item{
    display:inline-block;
    width:40%;
    border:4px solid #ccc;
}
.red{background-color:red;}
.blue{background-color:blue;}

JavaScript

var toggleColor = function(className){
    if(className){
        $(this).toggleClass(className);
    };
};

$(".left").on("click",$.proxy(toggleColor,$('.right'),"red"));
$(".right").on("click",$.proxy(toggleColor,$('.left'),"blue"));