<input type="button" value="START" id="test" onclick="console.log('1')" />
const el = document.getElementById('test')
el.addEventListener('click', () => console.log('2'));
el.addEventListener('click', () => console.log('3'));
{///
headers: {
"Content-Type": "application/json",
// 'Content-Type': 'application/x-www-form-urlencoded',
}
///
}
<textarea spellcheck lang="ru" ></textarea>