JSFiddle - React, Tailwind, and code Playground

HTML

<div id="Left" style="background-color:red">A</div>
<button type="button" onclick="socialExt()">Click me</button>

JavaScript

function socialExt()
{
    var elem =document.getElementById("Left");
    elem.style.width= parseInt(elem.style.width||0,10) + 240+'px' 
}