What is the difference between xhtml and html? Analysis of similarities and differences between xhtml and html-HTML Tutorial-php.cn

What is the difference between xhtml and html? Analysis of similarities and differences between xhtml and html

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Release： 2018-09-01 14:24:29

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This article mainly introduces the difference between HTML and xhtml. The similarities and differences between HTML and xhtml are all in it. Now let us look at this article together

一, First of all, let us first introduce the official explanation of the difference between HTML and xhtml:

HTML is a basic WEB web design language, and XHTML is a markup language based on XML. Similar, with some small but important differences, XHTML is XML that plays a role similar to HTML, so in essence, XHTML is a transitional technology that combines the power of XML (sort of) with the Most) simple features.

The differences between HTML and

2. The following are the major differences between XHTML and HTML:

XHTML requires correct nesting.
XHTMLAll elements must be closed.
XHTML is case sensitive.
XHTML documents must have a root element.

Now let’s look at the similarities and differences one by one:

1. Elements must be nested correctly

In HTML, some elements can be nested incorrectly within each other like this:

<b><i>这里是PHP中文网</b></i>

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In XHTML, all elements must be nested correctly with each other like this:

<b><i>This text is bold and italic</i></b>

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Tip: An easy mistake to make with nested lists is to forget that the inner list must be inside a li element, like this:

This is correct:

<ul>
  <li>百度</li>  
  <li>PHP中文网
    <ul>
      <li>html在线教程</li>
      <li>PHP在线教程</li>
    </ul>
  </li>
  <li>腾讯</li>
</ul>

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Note: In the correct code example, we inserted a tag after .

2.XHTML elements must be closed:

Non-empty tags must use closing tags.

This is wrong:

<p>这里是www.php.cn
<p>这里是PHP中文网

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This is correct:

<p>这里是www.php.cn</p>
<p>这里是PHP中文网</p>

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3.XHTML elements must be lowercase

XHTML specification Definition: Tag names and attributes are case-sensitive.

This is wrong:

<BODY>
<P>这里是PHP中文网</P>
</BODY>

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This is correct:

<body>
<p>这里是PHP中文网</p>
</body>

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4.XHTML documents must have a root element

All XHTML elements must be nested within the root element. All other elements can have child elements. Child elements must be paired and nested within their parent element. The basic document structure is as follows:

<html>
<head> ... </head>
<body> ... </body>
</html>

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The above is about the difference between HTML and xhtml. If you have any questions, you can ask them below.

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