<html>
<body>
<table border="1">
<tbody id="dynamic"></tbody>
</table>
<input type="button" value="add">
<script>
document.querySelector('input[type=button]').onclick = function () {
var tr = document.createElement('tr');
tr.innerHTML = '<td>1</td><td>2</td><td>3</td><td>4</td>';
document.querySelector('#dynamic').appendChild(tr);
}
</script>
</body>
</html>