我想僅在選擇組合框的值時顯示文本框，否則應將其隱藏。我需要在同一頁面中使用多個。感謝您的幫助。<label>1- Are there are friends/ neighbours/ family providing help ?</label><select class="form-control" name="formlist[any_friends_relatives_help3]" class="selincrease" id="edition"  onchange="func()" style="height: 5%;">  <option value="">choose...</option>  <?php      if (isset($forms['any_friends_relatives_help3'])) {      echo  '<option selected="selected" value="' . $forms['any_friends_relatives_help3']. '" disabled>' . $forms['any_friends_relatives_help3'] . '</option>' ;    echo '<option value="<?=$forms[\'any_friends_relatives_help3\'] ?? \'Yes\'?>">Yes</option>' ;  echo ' <option value="<?=$forms[\'any_friends_relatives_help3\'] ?? \'No\'?>">No</option>';  ?>  <?php  }    else {?>  <option value="<?=$forms['any_friends_relatives_help3'] ?? 'Yes'?>">Yes</option>  <option value="<?=$forms['any_friends_relatives_help3'] ?? 'No'?>">No</option>  <?php }?></select><div id="trhide">  <label>Please Specify:</label><br />  <textarea class="form-control" name="formlist[specify_help3]"><?=$forms['specify_help3'] ?? ''?></textarea></div><script type="text/javascript">  function func() {    var elem = document.getElementById("edition");    if (elem.value == "Yes") {      document.getElementById("trhide").style.visibility = "visible";    } else {      document.getElementById("trhide").style.visibility = "hidden";    }  }</script>如果我僅使用上面的一個，則它起作用，但是當我將另一個用于另一個選擇時，它們都不起作用。第二個代碼如下：<label>Shopping</label><select class="form-control" name="formlist[shopping3]" class="selincrease" id="change" style="height: 5%;"  required="required">  <option value="">choose...</option>  <?php            if (isset($forms['shopping3'])) {            echo  '<option selected="selected" value="' . $forms['shopping3']. '" disabled>' . $forms['shopping3'] . '</option>' ;          echo '<option value="<?=$forms[\'shopping3\'] ?? \'Self\'?>">Self</option>' ;  echo ' <option value="<?=$forms[\'shopping3\'] ?? \'Other\'?>">Other</option>';