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HTML DOCTYPE tag

HTML: <!DOCTYPE> tag

This HTML article explains to you how to use an HTML element called the <!DOCTYPE> tag with proper syntax and examples.

Description

The HTML <!DOCTYPE> tag is the starting line in the HTML code. <!DOCTYPE> tag tells the browsers what version of HTML the script is written and what to expect from this HTML code. This <!DOCTYPE> tag is also commonly referred to as the <!DOCTYPE> element.

 

Syntax of <!DOCTYPE>

The syntax for the <!DOCTYPE> tag changes between on the version of XHTML or HTML you are using. Now check out the most common usages of <!DOCTYPE>

The syntax in HTML5 is:

<!doctype html>

The syntax in HTML 4.01 is:

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

The syntax in XHTML 1.0 is:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

The syntax in XHTML 1.0 is:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

The syntax in XHTML 1.1 is:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

Tips and Notes

 Tip: The <!DOCTYPE> declaration is NOT case sensitive.

 

Browser Compatibility of <!DOCTYPE>

The <!DOCTYPE> tag has basic support with all these following browsers:

  • Chrome
  • Android
  • Firefox (Gecko)
  • Firefox Mobile (Gecko)
  • Internet Explorer (IE)
  • Edge Mobile
  • Opera
  • Opera Mobile
  • Safari (WebKit)
  • Safari Mobile

 

Example of <!DOCTYPE> Declaration

In the examples below we will discuss all the examples how to use HTML tags in HTML5, HTML 4.01 Transitional, , XHTML 1.1, XHTML 1.0 Transitional and XHTML 1.0 Strict.

 


 

HTML 4.01 Transitional Document

HTML 4.01 Transitional document, the <!DOCTYPE> tag code might looks like this as shown below:

html 4.01 doctype tag

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
<title>HTML 4.01 Transitional Example by www.home4cloud.com</title> 
</head> 
<body> 
<h1>Biggest Heading comes under this tag</h1> 
<p>This line is written inside the paragraph tag.</p> 
</body> 
</html>

In this above HTML 4.01 Transitional document, the <!DOCTYPE> tag code is on the first line which is not inside <html> tag.


XHTML 1.0 Transitional Document

XHTML 1.0 Transitional document, the <!DOCTYPE> tag code might looks like this as shown below:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 
<title>XHTML 1.0 Transitional Example in www.home4cloud.com</title> 
</head> 
<body> 
<h1>Biggest Heading comes under this tag</h1> 
<p>This line is written inside the paragraph tag.</p> 
</body> 
</html>

In this above XHTML 1.0 Transitional document, the <!DOCTYPE> tag code is on the first line which is not inside <html> tag.


XHTML 1.0 Strict Document

XHTML 1.0 Strict document, the <!DOCTYPE> tag code might looks like this as shown below:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 
<title>XHTML 1.0 Strict Example in www.home4cloud.com</title> 
</head> 
<body> 
<h1>Biggest Heading comes under this tag</h1> 
<p>This line is written inside the paragraph tag.</p> 
</body> </html>

In this above XHTML 1.0 Strict document, the <!DOCTYPE> tag code is on the first line which is not inside <html> tag.


XHTML 1.1 Document

XHTML 1.1 document, the <!DOCTYPE> tag code might looks like this as shown below:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml">
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 
<title>XHTML 1.1 Example in www.home4cloud.com</title> 
</head> 
<body> 
<h1>Biggest Heading comes under this tag</h1> 
<p>This line is written inside the paragraph tag.</p> 
</body> 
</html>

In this above XHTML 1.1 document, the <!DOCTYPE> tag code is on the first line which is not inside <html> tag.