HTML

HTML or Hyper Text Markup Language... mostly a dirivitive of SGML... is the markup language that web pages are written in. It was invented by Tim Burners-Lee in the early 1990's

Like most markup languages... the markup is in the tags and their attributes.

The markup is read by a parser that knows the markup and its tags (the language)...

The parser reads the markup because is is placed inside of angle brackets <MarkupTag>... a.k.a less than and greater than signs.

CREATED 2020-09-18 10:58:00.0

010-00-03-13

UPDATED 2020-09-19 12:53:37.0

DocType...

When writing an HTML page the First order of business is to identify what type of HTML you are using in the page. For this we use <!DOCTYPE>. This directive goes at the very top and it defines the type of document to render.

DocTypes have been narrowed down over the years and there are only a few left...

HTML 4 Strict...

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

HTML 4 Transitional...

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

XHTML or XML 1.0 Strict...

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

XHTML or XML 1.0 Transitional...

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

These doc types reference the DTD or the Document Type Definition. The DTD is a virtue of SGML which is what HTML was originally based on.

The DTD defines the language that is used in the document i.e. the tags and their attributes.

HTML 5

<!DOCTYPE HTML>

Why is HTML 5 so simple? Because HTML 5 is not based on SGML... therefore it has no DTD.

CREATED 2017-04-30 08:44:16.0

00-29-DB

UPDATED 2020-09-19 12:31:09.0

The Basic Page...

The basic html page consists on a single root element having exatly two children. It looks like this...

<!DOCTYPE HTML>
<html>
   <head>
      ...
   </head>
   <body>
      ...
   </body>
</html>

The two children of the document... i.e. the <html> tag... each have a specific purpose.

The <head> tag marks the defining section of the document while the <body> tag marks the displaying section of the document.

There are some exceptions... like the title tag that goes in the head section... is really a display type while the script tag that can go in the body section... is really a defining tag. But you can saftley consider this as a general rule.

CREATED 2012-07-07 14:07:06.0

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UPDATED 2020-09-19 12:31:05.0