16/10/04 22:10:22.18 px5zXLds.net
<input type="button"value="クリック" onclick="toggleDisp('disp')">
<table>
<tr><td>１行目：</td><td>aaaaaa</td></tr>
<tr id="disp"><td>２行目：</td><td>nnnnnn</td></tr>
</table>
table { border-collapse: separate }
table, td { border: 1px solid #000 }
#disp { display: none }
#disp.visible { display: table-row }
function toggleDisp(id) {
document.getElementById(id).classList.toggle("visible");
}