XHTML 1.0 Strict is a legacy version of HTML that was formulated as the XML equivalent to strict HTML 4.01. It includes only the elements and attributes that had not been marked deprecated in the HTML 4.01 specification.
Along with XHTML 1.0 Strict there were also XHTML 1.0 Transitional and Frameset versions.
XHTML was a name formerly used for a casting of HTML in XML syntax, to use with XML parsers.
http://en.wikipedia.org/wiki/Xhtml
XHTML 1.0 Strict does not include presentational tags (like <font> or <b>) or the <script> tag, meaning that all other languages other than HTML or XML (that are allowed) must be declared as either links to files (<link type="text/css" href="file.css" />, <script type="text/javascript" src="file.js" />) or declared within the file as valid tags (<style type="text/css">). Currently, JavaScript must be referenced using the src attribute of the <script> tag, you cannot type it directly onto your XHTML 1.0 Strict page.
XHTML 1.0 Strict has certain requirements that all pages with its doctype must meet:
The doctype
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">ensures that the web browser knows that the document type is XHTML 1.0 Strict.The character encoding can be added in two ways: 1.
<meta http-equiv="content-type" content="text/html; charset=UTF-8" />in the<head>element, or 2.<?xml version="1.0" encoding="utf-8"?>above the doctype. This ensures that odd characters, for example π, or 煸 are correctly displayed.
