JSFiddle - React, Tailwind, and code Playground

HTML

<span id="foo[1]">hello</span>
<span id="foo[2]">there</span>

JavaScript

$(function() {
    $('<input type="button" value="click me">').appendTo('body').click(function() {
        $('[id=foo\[1\]]').html('foo');
        $('[id=foo\[2\]]').html('bar');
    });
});