JSFiddle - React, Tailwind, and code Playground

HTML

<div id="tg"></div>

JavaScript

var REPLACE_HTML_STRING = '<a id="replace_a_tag" href="//test.html" target="_top" style="opacity:1; background-image:url({img_src});">{img_src}</a>';

var regExp = new RegExp('{img_src}', 'g');
var temp_html = '';
var img_src = '//element_1/element_2/test.png';
temp_html = REPLACE_HTML_STRING.replace(regExp, img_src);
console.log(temp_html);
document.getElementById( 'tg' ).innerHTML = temp_html;//innerText