JSFiddle - React, Tailwind, and code Playground

HTML

<div contenteditable="true">
  abcdefg
</div>

JavaScript

var a = $.trim($('div').text());
var b = '<img src="https://jsfiddle.net/img/logo.png" />';
var position = 5;
var output = a.substr(0, position) + b + a.substr(position);
$('div').html(output);