JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container_security" class="ui-dialog-content ui-widget-content" style="display: block; width: auto; min-height: 0px; height: 485.40000009536743px;">
    <div class="container_sec_class_container" style="display: block;">
        <div class="cont_sec_sec" style="height: 70px;">
            <p class="container_title">Name</p>
            <input id="container_name" readonly="readonly" type="text">
            <p class="container_secclass_title">Security Class</p>
            <dl class="container_security_class dropdown"> <dt>
                     <span class="parent">
                      <span class="container_secclass_dropdown">Shipping1 and Receiving1</span>
                </div>
                </div>
                </div>

JavaScript

$children = $("body").children();
while ($children.children().length > 0) {
    $children = $children.children();
}
//Now the variable $children is the set of elements at the bottom-most level of DOM.
console.log($children.attr('title', "bottom-most element in DOM tree"));