const button = document.getElementById('slide');
button.onclick = function () {
document.getElementById('container').scrollLeft += 20;
};
<div id="container">
<div id="content">Click the button to slide right!</div>
</div>
<button id="slide" type="button">Slide right</button>
#container {
width: 100px;
height: 100px;
border: 1px solid #ccc;
overflow-x: scroll;
}
#content {
width: 250px;
background-color: #ccc;
}