JSFiddle - React, Tailwind, and code Playground

HTML

<div style="height: 400px; width: 390px">
    
    <div id="jqm-home">
        <div id="page">
            <div id="sidebar">
                <div id="sidebarheader">
                    <header>Old Title</header>
                </div>
            </div>
        </div>
        <p onclick="UpdateHeader();">Click to update title</p>   
    </div>
</div>

JavaScript

function UpdateHeader() {
    $('#sidebar').find('header').html("New Title "); // IE8, nesting div's in the find fct. will not discover the child div
}