JSFiddle - React, Tailwind, and code Playground

HTML

<div tabindex="-1" id="scripted" contenteditable="true">Element Z (script-only focusable)</div>
<div id="test">Set Focus To Element Z</div>

CSS

div:focus {
    background-color: Aqua;
}

JavaScript

document.getElementById('test').onclick = function () {
    document.getElementById('scripted').focus();
    placeCaretAtEnd(document.getElementById('scripted'));
};

function placeCaretAtEnd(el) {
    el.focus();
    if (typeof window.getSelection != "undefined"
            && typeof document.createRange != "undefined") {
        var range = document.createRange();
        range.selectNodeContents(el);
        range.collapse(false);
        var sel = window.getSelection();
        sel.removeAllRanges();
        sel.addRange(range);
    } else if (typeof document.body.createTextRange != "undefined") {
        var textRange = document.body.createTextRange();
        textRange.moveToElementText(el);
        textRange.collapse(false);
        textRange.select();
    }
}