XHTML and CSS

HTML a short History

90's Tim Bernards-Lee HTML 1.0
93 MOSIAC
95-99 HTML 2.0-3.2 graphics, fonts, tables, javascript
DOM 0
99 HTML 4.0 - W3C
CSS - return to the structural roots
containment, Doctype DTD
DOM 1
2000- XHMTL
DOM2

HTML CSS
HTML tags were originally designed to the define the content of the document.
They were supposed to say
"This is a header", "this is a paragragh"
This is what we are going back to
Structure in the page, presentation in the CSS

XHTML
SGML split into XML and HTML
XML split into other MLs and XHTML
HTML is not XML - this is because HTML contains presentation whereas XML contains only structure.

XHTML
Mandatory Tags


Nesting
no overlapping


Containment
XML document must be well formed
XHTML will not validate if they are not well formed


Empty elements

Tag and element must be lower case
but values can be either lower or uppercase
and attribute values must be quoted " "

CSS
links w3 schools csszengarden

gives greater flexibility
loads faster
source code is easier to read
accessible to multimedia

SELECTOR and PROPERTY
SELECTOR = a defined style
PROPERTY = definition of an element of the style