當我單擊下拉列表中的值時遇到問題。它應該自動顯示權重（總計）。有人可以幫助我如何將默認情況下從標記分配下拉表單中的值自動調用為權重（總計）。標記分配代碼：<div class="form-row">  <label>Marks Allocation (%):</label>  <select name="percentage" class="form-control" oninput="this.className = ''">    <?php     $sql = mysqli_query($connection,"SELECT * FROM continous_assess");     while ($row=mysqli_fetch_array($sql))    { ?>    <option value="">      <?php echo $row['percentage']; ?>    </option>    <?php     }    ?>  </select></div>權重代碼：<div class="form-group">  <label>Weightage</label>  <input type="number" name="first" class="prc" />  <input type="number" name="second" class="prc" />  <input type="number" name="third" class="prc" />  <input type="number" name="fourth" class="prc" />  <input type="number" name="fifth" class="prc" />  <label>Total</label>  <output value="<?php echo $row['percentage'];?>"></output></div>