อยากทราบเกี่ยวกับการใช้คำสั่งซ่อนข้อความ TT

<script>
     function showDead(o){
	 if(o.value=="มีจริง"){
	  document.getElementById("deadDate").hidden=true;
		 }
	else{
	  document.getElementById("deadDate").hidden=false;
		}
	 }
     </script>

<tr id="deadDate" hidden>
      <td align="center" bgcolor="#FFFFFF"><a href="status_mon.php?p_idcard=<?php echo $row_ShowData['p_idcard']; ?>">เลือก</a></td>
      <td align="center" bgcolor="#FFFFFF"><?php echo $row_ShowData['p_idcard']; ?></td>
      <td align="left" bgcolor="#FFFFFF"><?php echo $row_ShowData['titlename']; ?><?php echo $row_ShowData['p_name']; ?>  <?php echo $row_ShowData['p_lastname']; ?></td>
      <td align="center" bgcolor="#FFFFFF"><?php echo $row_ShowData['p_status']; ?></td>
      
      <td align="center" bgcolor="#FFFFFF"><?php echo $row_ShowData['status_money']; ?></td>
      <td align="center" bgcolor="#FFFFFF"><?php echo $new_dateMon; ?></td>
      
    </tr>