JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div1">
    <input type="text" name="txt1" />
    <input type="radio" name="radio1" value="m" />
    <input type="radio" name="radio1" value="f" />
    <input type="checkbox" name="checkbox1" value="opt1" />
    <input type="checkbox" name="checkbox1" value="opt2" />
</div>
<button type="button" id="btn1">Click</button>

JavaScript

(function($) {
    var oldHTML = $.fn.html;

    $.fn.formhtml = function() {
        if (arguments.length) return oldHTML.apply(this, arguments);
        $("input,textarea,button", this).each(function() {
            this.setAttribute('value', this.value);
        });
        $(":radio,:checkbox", this).each(function() {
            // im not really even sure you need to do this for "checked"
            // but what the heck, better safe than sorry
            if (this.checked) this.prop("checked",true);
            else this.removeAttribute('checked');
        });
        $("option", this).each(function() {
            // also not sure, but, better safe...
            if (this.selected) this.setAttribute('selected', 'selected');
            else this.removeAttribute('selected');
        });
        return oldHTML.apply(this);
    };

    //optional to override real .html() if you want
    // $.fn.html = $.fn.formhtml;
})(jQuery);


$('#btn1').click(function() {
    alert($('#div1').formhtml());
    alert(document.getElementById('div1').innerHTML);

    var div1 = $('#div1');
    div1.clone().insertAfter(div1);
});