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What is the first line of code in html5

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Release： 2022-06-08 16:06:50

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In html5, the first line of code is "<!DOCTYPE>"; html5 document codes all start with "<!DOCTYPE>" as the first line. This code is a standard and universal The document type declaration of the markup language is used to tell the browser the version of the HTML code written in the page so that the browser can render it correctly.

What is the first line of code in html5

The operating environment of this tutorial: windows10 system, html5 version, Dell G3 computer.

The first line of code of html5

<!DOCTYPE>

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Any HTML document is the first line of code starting with the <!DOCTYPE> tag. This code will tell the browser the version of the HTML code written in the page so that the browser can render it correctly. In this sense, <!DOCTYPE> is not an HTML tag.

HTML 4.01 version of <!DOCTYPE> looks like this

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

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The <!DOCTYPE> declared in our sample file is HTML5, which is the latest standard for HTML. It is more concise and easier to read than the previous version.

!DOCTYPE does not belong to the HTML (an application under the Standard Universal Markup Language) tag. It is a document type declaration of the Standard Universal Markup Language. In HTML, it tells the browser the version of the markup used to write the page.

The<!DOCTYPE> declaration must be on the first line in the HTML5 document, before the tag. This tag tells the browser the HTML specification used by the document.

It is very important to specify !DOCTYPE in all HTML documents so that the browser understands the expected document type.

The !DOCTYPE in HTML 4.01 requires a reference to the DTD because HTML 4.01 is based on the Standard Universal Markup Language. HTML 5 is based on XML (a subset of the Standard Universal Markup Language), so there is no need to reference a DTD, but a !DOCTYPE is needed to regulate browser behavior (let browsers run the way they should).

Examples are as follows:

HTML5 document with the correct document type (!DOCTYPE):

<!DOCTYPE HTML>
 
<html>
      <head>
            <title>文档的题目</title>
      </head>
 
      <body>文档的内容</body>
</html>

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Recommended tutorial: "html video tutorial 》

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