<div>
<form class="form">
<input type="text" class="textview" readonly>
</form>
</div>
<div>
<button id="1" class="one">1</button>
</div>
const div = document.querySelector('.container')
const one = div.querySelector('.one')
const stroke = div.querySelector('input').value
one.onclick = function() {
stroke.innerHTML = 1;
}