我的 JavaScript 似乎忽略了数组中的第一个元素答案

【问题标题】：my JavaScript seems to be ignoring the first element in my array我的 JavaScript 似乎忽略了数组中的第一个元素
【发布时间】：2017-09-18 12:59:06
【问题描述】：

我正在使用 Moodle 中的评分表，我想在他们添加评论的地方添加一个标记，上面写着“学生添加了 cmets，请查看”。不幸的是，当您单击评论链接时，cmets 会加载 Ajax（或类似的东西）。学生提交作业后，Moodle 将文本“评论 (0)”添加到评分表中学生所在的行。（作业提交前，单元格为空白。）

所以我试图找到包含文本“评论”的单元格，然后检查 cmets 跨度中是否有零。

我已经稍微整理了一下 HTML，但我留下了单元格 c10，因为它实际上在 Moodle 上。

if (!document.getElementsByClassName('gradingtable')[0]) {
   /* do nothing */ 
} else {
    var table = document.getElementsByClassName('gradingtable')[0];
    var comments = table.getElementsByClassName('c10');
    
    for (var i=0, len=comments.length; i<len; i++){
        var commentText = comments[i].innerText;
        
        if (commentText.search('Comments') > -1){
            var enumerator = comments[i].getElementsByTagName('span')[0];
            
            if (enumerator.innerText.search('0') > -1){
                       // do nothing
            } else {
                var container = comments[i].getElementsByClassName('commentscontainer')[0];
                container.insertAdjacentHTML('afterend', '<div class="bluemsg">Student has added comments, please review.</div>'); 
            }
        }
    }
}

.bluemsg {
  background-color: #99ccff;
}


/* border and shading added for ease of viewing */
td { border: 1px solid #666 }

tr:nth-child(even) {background: #cecece}
tr:nth-child(odd) {background: #ffffff}

<h3> Moodle grading table (sample HTML)</h3>
<table class="gradingtable">
  <thead>
    <th>Col 0</th>
    <th>Col 1</th>
    <th>Col 2</th>
    <th>Col 3</th>
    <th>Col 4</th>
    <th>Col 5</th>
    <th>Col 6</th>
    <th>Col 7</th>
    <th>Col 8</th>
    <th>Col 9</th>
    <th>Col 10</th>
    <th>Col 11</th>
    <th>Col 12</th>
    <th>Col 13</th>
    <th>Col 14</th>
    <th>Col 15</th>
  </thead>
  <tbody>
    <tr>
      <td class="cell c0" id="mod_assign_grading_r0_c0">some text</td>
      <td class="cell c1" id="mod_assign_grading_r0_c1">some text</td>
      <td class="cell c2" id="mod_assign_grading_r0_c2">some text</td>
      <td class="cell c3 idnumber" id="mod_assign_grading_r0_c3">some text</td>
      <td class="cell c4 email" id="mod_assign_grading_r0_c4">some text</td>
      <td class="cell c5" id="mod_assign_grading_r0_c5">
        <div class="submissionstatus">No submission</div>
        <div class="overduesubmission">
          <font color="red">Assignment overdue </font>
        </div>
      </td>
      <td class="cell c6" id="mod_assign_grading_r0_c6">some text</td>
      <td class="cell c7" id="mod_assign_grading_r0_c7">
          some text</td>
      <td class="cell c8" id="mod_assign_grading_r0_c8">some text</td>
      <td class="cell c9" id="mod_assign_grading_r0_c9">
        some text
      </td>
      <td class="cell c10 jello" id="mod_assign_grading_r0_c10">
        <div class="commentscontainer">
          <div style="display:none" id="cmt-tmpl">
            <div class="comment-message">
              <div class="comment-message-meta"><span class="picture">___picture___</span><span class="user">___name___</span> - <span class="time">___time___</span></div>
              <div class="text">___content___</div>
            </div>
          </div>
          <div class="mdl-left"><a class="showcommentsnonjs" href="https://moodle.someurl.com/mod/assign/view.php?id=823272&amp;rownum=0&amp;useridlistid=59bfbd683690c374534060&amp;action=grading&amp;nonjscomment=1&amp;comment_itemid=281127&amp;comment_context=1272111&amp;comment_component=assignsubmission_comments&amp;comment_area=submission_comments">Show comments</a>
            <a
              class="comment-link" id="comment-link-59bfbd687894d" href="#" role="button" aria-expanded="false"><img id="comment-img-59bfbd687894d" src="https://moodle.someurl.com/theme/image.php/aardvark/core/1505694062/t/collapsed" alt="Comments" title="Comments"><span id="comment-link-text-59bfbd687894d">Comments (0)</span></a>
              <div id="comment-ctrl-59bfbd687894d"
                class="comment-ctrl">
                <ul id="comment-list-59bfbd687894d" class="comment-list">
                  <li class="first"></li>
                </ul>
                <div id="comment-pagination-59bfbd687894d" class="comment-pagination"></div>
                <div class="comment-area">
                  <div class="db"><textarea name="content" rows="2" id="dlg-content-59bfbd687894d" cols="20" style="color: grey;"></textarea></div>
                  <div class="fd" id="comment-action-59bfbd687894d"><a id="comment-action-post-59bfbd687894d" href="#">Save comment</a><span> | </span><a id="comment-action-cancel-59bfbd687894d" href="#">Cancel</a></div>
                </div>
                <div class="clearer"></div>
              </div>
          </div>
        </div>
      </td>
      <td class="cell c11" id="mod_assign_grading_r0_c11">-</td>
      <td class="cell c12" id="mod_assign_grading_r0_c12"></td>
      <td class="cell c13" id="mod_assign_grading_r0_c13">some text</td>
      <td class="cell c14" id="mod_assign_grading_r0_c14">some text</td>
      <td class="cell c15" id="mod_assign_grading_r0_c15">some text</td>
    </tr>
    <tr>
      <td class="cell c0" id="mod_assign_grading_r1_c0">some text</td>
      <td class="cell c1" id="mod_assign_grading_r1_c1">some text</td>
      <td class="cell c2" id="mod_assign_grading_r1_c2">some text</td>
      <td class="cell c3 idnumber" id="mod_assign_grading_r1_c3">some text</td>
      <td class="cell c4 email" id="mod_assign_grading_r1_c4">some text</td>
      <td class="cell c5" id="mod_assign_grading_r1_c5">
        <div class="submissionstatus">No submission</div>
        <div class="overduesubmission">
          <font color="red">Assignment overdue </font>
        </div>
      </td>
      <td class="cell c6" id="mod_assign_grading_r1_c6">some text</td>
      <td class="cell c7" id="mod_assign_grading_r1_c7">
          some text</td>
      <td class="cell c8" id="mod_assign_grading_r1_c8">some text</td>
      <td class="cell c9" id="mod_assign_grading_r1_c9">
        some text
      </td>
      <td class="cell c10 jello" id="mod_assign_grading_r1_c10">
        <div class="commentscontainer">
          <div style="display:none" id="cmt-tmpl">
            <div class="comment-message">
              <div class="comment-message-meta"><span class="picture">___picture___</span><span class="user">___name___</span> - <span class="time">___time___</span></div>
              <div class="text">___content___</div>
            </div>
          </div>
          <div class="mdl-left"><a class="showcommentsnonjs" href="https://moodle.someurl.com/mod/assign/view.php?id=823272&amp;rownum=0&amp;useridlistid=59bfbd683690c374534060&amp;action=grading&amp;nonjscomment=1&amp;comment_itemid=281127&amp;comment_context=1272111&amp;comment_component=assignsubmission_comments&amp;comment_area=submission_comments">Show comments</a>
            <a
              class="comment-link" id="comment-link-59bfbd687894d" href="#" role="button" aria-expanded="false"><img id="comment-img-59bfbd687894d" src="collapsed.png" alt="Comments" title="Comments"><span id="comment-link-text-59bfbd687894d">Comments (1)</span></a>
              <div id="comment-ctrl-59bfbd687894d"
                class="comment-ctrl">
                <ul id="comment-list-59bfbd687894d" class="comment-list">
                  <li class="first"></li>
                </ul>
                <div id="comment-pagination-59bfbd687894d" class="comment-pagination"></div>
                <div class="comment-area">
                  <div class="db"><textarea name="content" rows="2" id="dlg-content-59bfbd687894d" cols="20" style="color: grey;"></textarea></div>
                  <div class="fd" id="comment-action-59bfbd687894d"><a id="comment-action-post-59bfbd687894d" href="#">Save comment</a><span> | </span><a id="comment-action-cancel-59bfbd687894d" href="#">Cancel</a></div>
                </div>
                <div class="clearer"></div>
              </div>
          </div>
        </div>
      </td>
      <td class="cell c11" id="mod_assign_grading_r1_c11">-</td>
      <td class="cell c12" id="mod_assign_grading_r1_c12">-</td>
      <td class="cell c13" id="mod_assign_grading_r1_c13">some text</td>
      <td class="cell c14" id="mod_assign_grading_r1_c14">some text</td>
      <td class="cell c15" id="mod_assign_grading_r1_c15">some text</td>
    </tr>
  </tbody>
</table>

【问题讨论】：

标签： javascript html moodle

【解决方案1】：

看起来您正在检查不同字符串（跨度标记之一）中的零，而不是注释/数字字符串。您可以替换： if (enumerator.innerText.search('0') > -1){ 和： if (commentText.search('0') > -1){

您可能根本不需要枚举变量。

【讨论】：