Doctype

How to Fix

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:

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" >