javascript - 每次使用 jQuery，scrollTop() 返回零

Question

我在使用 jQuery 时遇到问题 scrollTop()函数 $.each.每次，不管多少<div class="panel"></div>元素是，scrollTop()函数返回零。我在 Get height of multiple divs with jquery 中使用了代码线程，只改变了height()至 scrollTop()函数(height() 仍然返回零)。

这是我创建的代码，因此理解问题会容易得多。

var acc = document.getElementsByClassName("accordion");
var i;

for (i = 0; i < acc.length; i++) {
  acc[i].onclick = function() {
    this.classList.toggle("active");
    var panel = this.nextElementSibling;
    if (panel.style.maxHeight) {
      panel.style.maxHeight = null;
    } else {
      panel.style.maxHeight = panel.scrollHeight + "px";
    }
  }
}

var $panel = $('.panel'),
  totalHeight = 0;

$.each($panel, function() {
  totalHeight += $(this).scrollTop();
});

alert(totalHeight);

button.accordion {
  background-color: #eee;
  color: #444;
  cursor: pointer;
  padding: 18px;
  width: 100%;
  border: none;
  text-align: left;
  outline: none;
  font-size: 15px;
  transition: 0.4s;
}

button.accordion.active,
button.accordion:hover {
  background-color: #ddd;
}

button.accordion:after {
  content: '\002B';
  color: #777;
  font-weight: bold;
  float: right;
  margin-left: 5px;
}

button.accordion.active:after {
  content: "\2212";
}

div.panel {
  padding: 0 18px;
  background-color: white;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.2s ease-out;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button class="accordion">Lėšų išsiėmimai</button>
<div class="panel">
  <div>
  </div>
  <table>
    <tbody>
      <tr>
        <th>Data</th>
        <th>12 val.</th>
        <th>0.01 Eur</th>
        <th>Data</th>
        <th>24 val.</th>
        <th>0.02 Eur</th>
      </tr>

      <tr>
        <td colspan="3"></td>
        <td>2017-06-26 01:39:16</td>
        <td colspan="2">+</td>
      </tr>

      <tr>
        <td colspan="3"></td>
        <td>2017-06-24 14:43:50</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td>2017-06-24 14:43:27</td>
        <td colspan="2">+</td>

        <td>2017-06-15 14:43:43</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td>2017-06-15 14:42:23</td>
        <td colspan="2">+</td>

        <td>2017-06-07 16:34:04</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td>2017-06-07 16:33:36</td>
        <td colspan="2">+</td>

        <td>1970-01-01 03:00:00</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td>2017-06-06 15:13:41</td>
        <td colspan="2">+</td>

        <td>1970-01-01 03:00:00</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td style="background: #0E82A7;">Iš viso</td>
        <td style="background: #0E82A7;" colspan="2">0.0400 Eur</td>
        <td style="background: #0E82A7;"></td>
        <td style="background: #0E82A7;" colspan="2">0.1200 Eur</td>
      </tr>

    </tbody>
  </table>
</div>
<div class="panel">
  <div>
  </div>
  <table>
    <tbody>
      <tr>
        <th>Data</th>
        <th>12 val.</th>
        <th>0.01 Eur</th>
        <th>Data</th>
        <th>24 val.</th>
        <th>0.02 Eur</th>
      </tr>

      <tr>
        <td colspan="3"></td>
        <td>2017-06-26 01:39:16</td>
        <td colspan="2">+</td>
      </tr>

      <tr>
        <td colspan="3"></td>
        <td>2017-06-24 14:43:50</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td>2017-06-24 14:43:27</td>
        <td colspan="2">+</td>

        <td>2017-06-15 14:43:43</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td>2017-06-15 14:42:23</td>
        <td colspan="2">+</td>

        <td>2017-06-07 16:34:04</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td>2017-06-07 16:33:36</td>
        <td colspan="2">+</td>

        <td>1970-01-01 03:00:00</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td>2017-06-06 15:13:41</td>
        <td colspan="2">+</td>

        <td>1970-01-01 03:00:00</td>
        <td colspan="2">+</td>
      </tr>
      <tr>
        <td style="background: #0E82A7;">Iš viso</td>
        <td style="background: #0E82A7;" colspan="2">0.0400 Eur</td>
        <td style="background: #0E82A7;"></td>
        <td style="background: #0E82A7;" colspan="2">0.1200 Eur</td>
      </tr>

    </tbody>
  </table>
</div>

Answer 1

显然 height 属性将返回 0，因为您的面板设置为

max-height:0;

代码运行时。现在，函数:

scrollTop()

将检查窗口的滚动条，您可能正在寻找的是:

$(this).offset().top

这是 fiddle :https://jsfiddle.net/08gccLph/

希望对您有所帮助:)