JSFiddle - React, Tailwind, and code Playground

HTML

<div id="a"></div>

CSS

div {
    width: 100%;
    height: 300px;
}

JavaScript

var first = "http://icondock.com/wp-content/themes/idock/images/featured-origami.png";
var second = "http://icondock.com/wp-content/themes/idock/images/featured-rocky.png";
var bgFormat = "url({1}) left top no-repeat, url({2}) bottom right no-repeat";

var cssBackground = bgFormat.replace("{1}", first).replace("{2}", second);

console.log(cssBackground);
    
$("#a").css("background", cssBackground);