The <head> tag starts the document header and the </head> tag
ends it. These tags are used only once in each HTML document.
NOTE: This tag is required for an XHTML document to validate.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<title>Welcome to HTML</title>
</head>
<body>
Welcome to the world of HTML!
</body>
</html>
