JSFiddle - React, Tailwind, and code Playground

HTML

<form id="myForm" method="post" action="/echo/html/">
    <input name="html" value="123" />
    <input type="submit" name="submit" />
</form>

JavaScript

function submitMyForm(oldForm, button) {

    var input = document.createElement("input");
    input.type = "hidden";
    input.name = "submit";
    input.value = button.value || "Submit";
    oldForm.removeChild(button);
    oldForm.appendChild(input);

    var newForm = document.createElement('form');
    newForm.submit.call(oldForm);
}


var frm = document.getElementById("myForm");
var btn = frm.submit;
submitMyForm(frm, btn);