小编Iav*_*vor的帖子

我可以使用带有select的标签元素吗？

我看到的大多数地方仅使用输入元素标注示例.

标准对标签关联有什么看法？

它是一个有效的HTML标记吗？

<label for="id_select"> Options </label>
<select id="id_select" autofocus="true">
  <option value="1"> Option1 </option>
  <option value="2"> Option2 </option>
</select>

问题:这四个承诺有什么区别？

doSomething().then(function () { return doSomethingElse(); });

doSomething().then(function () { doSomethingElse(); });

doSomething().then(doSomethingElse());

doSomething().then(doSomethingElse);

我要创建传单标记群集组，并要添加我写了下面提到的代码的所有标记。但是我得到了错误TypeError: L.markerClusterGroup is not a constructor

我没有得到脚本或我编写的代码中的错误

 <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.7/leaflet.css">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.7/leaflet.js"></script>
  <link rel="stylesheet" href="https://unpkg.com/leaflet.markercluster@1.0.3/dist/MarkerCluster.css">

<script src="https://unpkg.com/leaflet.markercluster@1.3.0/dist/leaflet.markercluster.js"></script>
<script src='https://unpkg.com/leaflet.markercluster@1.3.0/dist/leaflet.markercluster-src.js'></script>

var markers = L.markerClusterGroup();
markers.addLayer(L.marker(getRandomLatLng(map)));
map.addLayer(markers);