1.사진과 같은 화면을 만들고 "추가하기"버튼을 누르면 3다음에 4가 들어간 칸이 나오게 해주세요.
<!DOCTYPE html>
<html>
<head>
<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<script>
function submitjava(){
$('#mytable > tbody > tr').append('<td>4</td>');
}
</script>
</head>
<body>
<table id = "mytable" border="1">
<tbody>
<tr>
<td>1</td>
<td>2</td>
<td>3</td>
</tr>
</tbody>
</table>
<button type="button" onclick="submitjava();">클릭</button>
</body>
</html>