JSFiddle - React, Tailwind, and code Playground

HTML

<div class="first-div"></div>
<div class="second-div">
    <div class="inner-div">Test</div>
</div>
<button onclick="toggle()">Toggle Border</button>

CSS

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
.first-div {
    background-color: red;
    min-height: 50px;
}
.second-div {
    background-color: blue;
    min-height: 50px;
    overflow:auto;
}
.inner-div {
    margin: 10px;
    text-align: center;
}

JavaScript

toggle = function () {
    if (document.getElementsByClassName('second-div')[0].style.border) {
        document.getElementsByClassName('second-div')[0].style.border = "";
    } else {
        document.getElementsByClassName('second-div')[0].style.border = "5px solid";
    }
};