JSFiddle - React, Tailwind, and code Playground

HTML

<form method="POST">
  <input id="first" type="text" name="first" value="1" />
  <input id="second" type="text" name="second" value="2" />
  <button type="submit" id="btn">SEND TO SERVER</button>
</form>

JavaScript

$("#btn").click(function(e) {
	e.preventDefault();
  sendToServerMyData();
});

function sendToServerMyData() {
	alert("отправляем AJAX-запрос");
}