JSFiddle - React, Tailwind, and code Playground

HTML

<div id='div1' contenteditable>Text inside div </div>

<span>Insert random text</span>

CSS

#div1
{
    display:block;
    border:solid 1px #ccc;
    width:400px;
    height:200px;
}

JavaScript

function pasteHtmlAtCaret(html) {
    var sel, range;
    if (window.getSelection) {
        // IE9 and non-IE
        sel = window.getSelection();
        if (sel.getRangeAt && sel.rangeCount) {
            range = sel.getRangeAt(0);
            range.deleteContents();

            // Range.createContextualFragment() would be useful here but is
            // non-standard and not supported in all browsers (IE9, for one)
            var el = document.createElement("div");
            el.innerHTML = html;
            var frag = document.createDocumentFragment(), node, lastNode;
            while ((node = el.firstChild)) {
                lastNode = frag.appendChild(node);
            }
            range.insertNode(frag);

            // Preserve the selection
            if (lastNode) {
                range = range.cloneRange();
                range.setStartAfter(lastNode);
                range.collapse(true);
                sel.removeAllRanges();
                sel.addRange(range);
            }
        }
    } else if (document.selection && document.selection.type != "Control") {
        // IE < 9
        document.selection.createRange().pasteHTML(html);
    }
}


$("span").click(function() {
    pasteHtmlAtCaret("Some <b>random</b> text");
});