JSFiddle - React, Tailwind, and code Playground

HTML

<div id="base">
    <ul class="list">
        <li class="remove">wrong</li>
        <li>one</li>
        <li>two</li>
        <li>three</li>
    </ul>
</div>

JavaScript

function checkDomStructure() {
    var elementNodeType = 1;
    var rootEl = document.getElementById('base');
    if ( !rootEl ) return false;
    if ( rootEl.nodeName != 'DIV' ) return false;
    var listNodes = rootEl.getElementsByClassName('list');
    if ( listNodes.length > 1 ) return false;
    var listEl = listNodes[0];
    if ( listEl.nodeName != 'UL' ) return false;
    var text = '';
    var wasWrong = false;
    for (var i=0; i<listEl.childNodes.length; i++) {
        var currNode = listEl.childNodes[i];
        if ( currNode.nodeType == elementNodeType ) {
            if ( currNode.nodeName != 'LI' ) return false;
            var content = currNode.textContent;
            if ( currNode.className == 'remove' && content == 'wrong' ) {
                wasWrong = true;
            } else {
                text += content + ' ';
            }
        }
    }
    if ( text != 'one two three ' ) return false;
    return wasWrong;
}

// --- service part ---
var res = false;
try {
    res = checkDomStructure();
} catch (e) {}
var msgEl = document.createElement('h1');
msgEl.textContent = 'Sorry, try again.';
if (res) {
    msgEl.textContent = 'Congratulation!';
    msgEl.style.color = 'green';
}
document.body.appendChild(msgEl);