JSFiddle - React, Tailwind, and code Playground

HTML

<label>
    <input type="checkbox" id="powermail_field_doruovaciaadresa2_1" checked="checked" />
    Show/hide
</label>
<div id="powermail_fieldwrap_331">Lorem ipsum</div>

JavaScript

var elem = document.getElementById('powermail_fieldwrap_331'),
    checkBox = document.getElementById('powermail_field_doruovaciaadresa2_1');
checkBox.checked = false;
checkBox.onchange = function() {
    elem.style.display = this.checked ? 'block' : 'none';
};
checkBox.onchange();