JSFiddle - React, Tailwind, and code Playground

HTML

<p id="in">Hello, <i>World!</i></p>
<p id="out">xxx</p>

JavaScript

var getInnerText = function (element) {
    var nodes = element.childNodes,
        i = 0,
        len = nodes.length,
        text = '',
        node;
    for (; i < len; i++) {
        node = nodes[i];
        if (node.nodeType === 3 || node.nodeType === 4) {
            // 3 means text node, 4 means cdata
            text += node.nodeValue;
        } else if (node.nodeType !== 8) { // Skip comments
            text += getInnerText(node);
        }
    }
    return text;
};


var node = document.getElementById('in');
var out = document.getElementById('out');
out.innerHTML = getInnerText(node);