Send messages to WhatsApp (web version only) programmatically.

whatsapp-sendMessage.js

function sendMessage (message) {
  window.InputEvent = window.Event || window.InputEvent;

  var event = new InputEvent('input', {
    bubbles: true
  });

  var textbox = document.querySelector('div._3u328');

  textbox.textContent = message;
  textbox.dispatchEvent(event);

  document.querySelector("button._3M-N-").click();
}