段落选择器内的标题不起作用答案

【问题标题】：Heading inside paragraph selector not working段落选择器内的标题不起作用
【发布时间】：2020-10-01 04:32:07
【问题描述】：

我想将<p> 标记的所有子项的背景颜色更改为绿色。但是我写的代码不起作用。但是，如果我将<p> 标签更改为<div>，它就可以工作了。但我需要它使用 jQuery 高级选择器处理 <p> 标记

代码：

$(document).ready(() => {
  //Change background color of children to green
  //Below code is not working
  $("#intro").children().each(function() {
    $(this).css("background-color", "green");
  });
  //Show only first 2 list item
  $('ol li').hide().slice(0, 2).show();
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.0/jquery.min.js"></script>
<p id="intro">jQuery is a lightweight, "write less, do more" JavaScript library.
  <h6>The purpose of jQuery is to make it much easier to use JavaScript on your website</h6>
</p>
<ol>
  <li>HTML/DOM manipulation</li>
  <li>CSS manipulation</li>
  <li>Effects and animations</li>
  <li>AJAX</li>
</ol>

【问题讨论】：

标签： javascript html jquery css jquery-selectors

【解决方案1】：

h 不是p 的有效子代

Paragraph P

段落是块级元素，如果在关闭 </p> 标记之前解析另一个块级元素，则会自动关闭。

允许的内容：Phrasing content

渲染出来的 HTML 变成了

<p id="intro">jQuery is a lightweight, "write less, do more" JavaScript library.
</p><!-- inserted by browser -->
<h6>The purpose of jQuery is to make it much easier to use JavaScript on your website</h6>
<p><!-- inserted by browser -->
</p>

你可以这样做：

$(document).ready(() => {
  //Change background color of children to green
  //Below code is now working
  $("#intro").children().each(function() {
    $(this).css("background-color", "green");
    $('<br />').insertBefore(this); // because of the inline-block
  });
  //Show only first 2 list item
  $('ol li').hide().slice(0, 2).show();
})

.h6 { 
    display: inline-block;
    font-size: .67em;
    margin-top: 2.33em;
    margin-bottom: 2.33em;
    margin-left: 0;
    margin-right: 0;
    font-weight: bold;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.0/jquery.min.js"></script>
<p id="intro">jQuery is a lightweight, "write less, do more" JavaScript library.
  <span class="h6">The purpose of jQuery is to make it much easier to use JavaScript on your website</span>
</p>
<ol>
  <li>HTML/DOM manipulation</li>
  <li>CSS manipulation</li>
  <li>Effects and animations</li>
  <li>AJAX</li>
</ol>

【讨论】：