<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<textarea id="area"></textarea>
<div id="label">Не печатает...</div>
<script>
var timer, show = document.querySelector('#label');
document.querySelector('#area').oninput = function () {
window.clearTimeout(timer);
show.innerHTML = 'Печатает...';
window.setTimeout(function () {
show.innerHTML = 'Не печатает...'
}, 1500)
}
</script>
</body>
</html>