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Doctype Test

What is it?

Check for doctype declaration. A document type declaration, or DOCTYPE, defines which version of (X)HTML your webpage is using. Proper doctype declaration assists with proper page rendering and functioning of web documents in compliant browsers.

Pass rate:

  • Top 100 websites: 100%
  • All websites: 98%
Pass rates of Top 100 US websites
2021

100%

2022

100%

2023

100%

100

75

50

25

0

How do I fix it ?

Always add the <!DOCTYPE> declaration to your HTML documents, so that the browser knows what type of document to expect. This declaration must be the very first thing in your HTML document, before the <html> tag. You can see below the most common <!DOCTYPE> declarations:

  • HTML 5:
    <!DOCTYPE html>
    
  • HTML 4.01 Strict:
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
    
  • HTML 4.01 Transitional:
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    
  • XHTML 1.0 Strict:
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
    
  • XHTML 1.0 Transitional:
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    
  • XHTML 1.1:
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
    
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