我试图在日历中相应地显示我的活动名称。名称都是从本地存储中检索的。但是，我似乎无法将名称附加到月份div。在调试时，它说“无法读取'appendChild'的属性为null”。
以下是我的代码：
EXIT_FAILUREjavascript：
<table border="1" id="list" style="width:40%">
<caption style="text-align:center; margin:5px; font-weight:bold; font-size:30px; margin-bottom:10px">
LIST OF EVENTS
</caption>
<tr><th>Month</th><th>Events Name</th></tr>
<tr>
<td>January</td>
<td>
<ul id="jan">
</ul>
</td>
</tr>
<tr>
<td>February</td>
<td>
<ul id="feb">
</ul>
</td>
</tr>
<tr>
<td>March</td>
<td>
<ul id="mar">
</ul>
</td>
</tr>
<tr>
<td>April</td>
<td>
<ul id="apr">
</ul>
</td>
</tr>
<tr>
<td>May</td>
<td>
<ul id="may">
</ul>
</td>
</tr>
<tr>
<td>June</td>
<td>
<ul id="jun">
</ul>
</td>
</tr>
<tr>
<td>July</td>
<td>
<ul id="july">
</ul>
</td>
</tr>
<tr>
<td>August</td>
<td>
<ul id="aug">
</ul>
</td>
</tr>
<tr>
<td>September</td>
<td>
<ul id="sept">
</ul>
</td>
</tr>
<tr>
<td>October</td>
<td>
<ul id="oct">
</ul>
</td>
</tr>
<tr>
<td>November</td>
<td>
<ul id="nov">
</ul>
</td>
</tr>
<tr>
<td>December</td>
<td>
<ul id="dec">
</td>
</tr>
</table>