[Malleys]

<div id="test_1">Пример</br>
<input type="button" value="+" onclick="zoom(document.getElementById('test_1'), 0.1);">
<input type="button" value="-" onclick="zoom(document.getElementById('test_1'), -0.1);">
</div>

<script>

function zoom(element, amount) {
  element._zoom = element._zoom || 1;
  element.style.transform = 'scale(' + (element._zoom = (element._zoom + amount)) + ')';
  element.style.transformOrigin = '0 0';
}

</script>