javascript - 计算jquery中存储在变量内的span数量

Question

基本上尝试计算存储在 items 变量中的跨度数量，但 length 始终返回 0

var items = '<br><span class="holiday">Buddha Jayanti</span><br><span class="workingDay">Shiva Ratri</span>';

var length = $(items).find('span').length;
alert(length); //returning 0

我在这里缺少什么吗？

Answer 1

因为span位于元素集的根部，所以.find()不会返回任何元素，需要使用.filter()相反

var items = '<br><span class="holiday">Buddha Jayanti</span><br><span class="workingDay">Shiva Ratri</span>';

var length = $(items).filter('span').length;
snippet.log(length);

<!-- Provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<小时/>

如果也有可能有后代 span 元素，则另一个选择是

var items = '<br><span class="holiday">Buddha Jayanti</span><br><span class="workingDay">Shiva Ratri</span><div><br><span class="workingDay">some value</span></div>';

var length = $('<div />', {
  html: items
}).find('span').length;
snippet.log(length);

<!-- Provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>