CSC151 2003F, Class 3: HTML

Admin
* Collect "homework"
* Assignment: Read quick guide to HTML
* Different sections of 151 are different
* Why have class on labor day?

Overview:
* Getting started in MathLAN
* Quick tour of course web
* About markup languages
* Designing markup languages
* The design of HTML
* HTML basics
* A sample page

Screwups in the instructions:
* "2002F" should be "2003F" in the course URL
* Not much else (email not required)

Markup languages and HTML
* Most of this semester on the programming language Scheme
  * Intended for expressing algorithms
* Other languages include markup languages
* Study because you need experience with formal languages

Markup languages
* A language that's more for design than for algorithms
  * For talking about organization of information more 
    than processing information
* What's a language?
  * A system of words arranged in a specific syntax
  * Syntax: The way in which you arrange words
  * "Semantics" gives meaning to the legal phrases
* "Natural language" (used by humans) from "formal langauge"
  (no leeway in validity)

What kinds of things do you want to say about information?
* These things have bullet points before them
  * These things have a different kind of bullet points
    before them
* The page is arranged into categories.  Each category begins with a title that is in boldface.
* The word "EBoard" is a link (it's purple and underlined) to another document.

We've said different kinds of things:
* Some have to do with appearance: "It's bold"; "It's indented 3 inches from left margin"; "It's prefixed by a bullet".
* Some have to do with roles: "It's the name of a category". "It's a link"

Some markup languages focus on appearance
Some markup languages focus on roles
(Sometimes one implies the other)

Why focus on appearance?
* Appearance can clearly denote the role of the text.
* To help ensure that you make pretty documents so that people will want to read them

Why focus on roles?
* To avoid confusion: Sometimes making a document pretty makes it confusing
* To require authors to think about roles

--- 

On to a little practice:

HTML, a hypertext markup language designed in early 1990's
by Tim Berners-Lee at CERN. 
* Key design goal: "Easy for Physicists"
* Other design goal: Markup can be indicated by normal
  typewriter.

Conclusion (taken from SGML): Surround text with "tags" that indicate appearance or role.
* A tag is word surrounded by <, >
* End tags have a slash after the <
* E.g., <p> ... </p>
* Twenty or so basic tags:
  p: paragraph
  b: bold
  i: italic
  u: underline
  li: list item
  ul: unordered list (bullets etc.)
  ol: ordered list (numbered or lettered)
  em: emphasize
  strong: strongly emphasize
  h1: heading in a document (e.g., doc title)
  h2: slightly lower level heading (e.g. sec title)
  h3: 
  ...
  h6:
  hr: Horizontal rule
  a: anchor or link

<h2>Notes</h2>
<ul>
<li>For those of you wondering about the issue, the two sections of CSC151 follow somewhat different paths through the material. Our section starts a little bit slower (and covers HTML directly), but we sometimes move more quickly through other topics.</li>
<li>I forgot what else goes here.</li>
</ul>

Unfortunately, life isn't quite that simple.
* You need to describe which version of HTML you are using.
* You have to say what language you're using.
* You have to say what character set you're using.