HTML Guide
An end tag </p> has been found that cannot be matched for an opening tag <p>. Most of the times this is due to closing the same tag twice, for example:
<p>some text</p></p>Related W3C validator issues
A <p> element cannot be placed inside a <noscript> tag within the <head> section.
According to the HTML specification, the <head> element must only contain metadata, such as <title>, <meta>, <link>, <script>, and <style>. The <noscript> element is allowed in <head>, but it must only contain elements that are valid in head, not flow content like <p>. The <p> (paragraph) tag is flow content meant for the <body>. For fallback content in <head>, only metadata elements are allowed.
Incorrect example:
<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Example</title>
    <noscript>
      <p>JavaScript is disabled.</p>
    </noscript>
  </head>
  <body>
  </body>
</html>Correct approaches:
- 
Remove the <p> from <noscript> in <head>:    - If you must include fallback styles or links in case JavaScript is disabled, use only metadata tags.
 
<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Example</title>
    <noscript>
      <link rel="stylesheet" href="no-js.css">
    </noscript>
  </head>
  <body>
  </body>
</html>- 
Place textual fallback content in the <body> instead:    - Moving the <noscript> block with flow content (such as <p>) to the body ensures validity.
 
<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Example</title>
  </head>
  <body>
    <noscript>
      <p>JavaScript is disabled.</p>
    </noscript>
  </body>
</html>Remember: Do not use <p> (or any flow content) in <noscript> inside <head>. Use such content only in the body.
A closing tag </li> has been found, but there were open elements nested inside the <li>. You need to close the nested elements before you close the <li>.
A closing tag </li> has been found, but there were open elements nested inside the <li>. You need to close the nested elements before you close the <li>.
For example:
<li>
  <span>example
</li>The above is invalid because you need to close the <span> tag before you close the <li>.
This would be valid:
<li>
  <span>example</span>
</li>Your HTML markup contains an end tag for X, but there are nested open elements that need to be closed first. For example, <li><span>example</li> is invalid because you need to close the <span> tag before you close the <li>. This would be valid: <li><span>example</span></li>.
And end tag for element X has been found with no corresponding opening tag for it. Most of the times this is due to closing the same tag twice.