Introduction And Overview
This is information from Chapter 1 of your text, with some additional material.
  1. Web Pages.
    1. The Internet started to have users (not just its creators) during the 1980s.
      1. This was oriented to remote use of a computer, and download of specific files by name.
      2. Very text-oriented; no WWW yet.
    2. Tim Berners-Lee invented the World-Wide-Web at CERN, including HTML and HTTP (see below).
      1. Wanted a convenient way to use the Internet to share the latest physics research results.
      2. Created the HTML language to write pages, and the HTTP network protocol to transfer them.
      3. Early web was a way to link static documents (with figures).
    3. Initial model
      1. Client-server
        1. Client sends a request for a particular URL.
        2. The URL refers to a particular file on the server.
        3. Server responds, with the file contents or error indication.
      2. Pages are stored on the server machine. Server copies them out.
      3. Interaction is clicking on links.
    4. Common Gateway Interface (CGI). (Not to be confused with the “Computer-Generated Imagery” in your favorite movie.)
      1. The earliest form of dynamic web page: Can respond to input rather than deliver a pre-made file.
      2. The file the URL refers to is a program instead of text.
      3. The program is run, and the output is sent to the browser.
      4. Usually, the output is HTML.
      5. Can use any programming language supported by the server system.
    5. Server-side programming.
      1. Similar to CGI, but uses languages specialized to generate HTML.
      2. Usually run inside the server or in a dedicated process, rather than as a separate program.
      3. There are others, but we will use a popular language called PHP.
    6. Client-side programming: Javascript.
      1. A browser obeys the instructions in HTML.
        1. Produced by the server to direct the display.
        2. Passive: does not respond to the user.
        3. Page stays the same until the user clicks to get a new one.
      2. Javascript can be added to the HTML, and the browser obeys that, too.
        1. Javascript is active, and can respond directly to the mouse and keyboard.
        2. Makes a page much faster since it can respond to the user without making a request to the server.
    7. Compare: Server Side Client Side
    8. Ajax.
      1. Let the Javascript interact directly with the server.
      2. Modify the page with server data, but no full page markup required. Google Maps.
  2. Changes in HTML
    1. The WWW was an instant hit.
    2. Randomly expanded for some years.
      1. Netscape, the first commercial browser, was very successful.
      2. Microsoft responded by creating Internet Explorer.
      3. Period of not-always-healthy competition known as the browser wars.
      4. Divergence of browsers made it hard to know how to write your page.
      5. Eventual convergence on industry standards.
    3. The HTML standard remains in flux.
      1. Last formal standard seems to be HTML 5, issued by the World Wide Web Consortium (W3C).
      2. Since then, the W3C and the Web Hypertext Application Technology Working Group (WHATWG) had been issuing competing standards. They have recently signed a truce intended to end that.
      3. Development now proceeds as a “living standard” which never becomes fixed: There will not be an HTML 6; just this week's iteration.
  3. Cascading Style Sheets (CSS).
    1. A language for describing the appearance of a page.
    2. CSS is embedded inside HTML.
    3. Helps make sure pages look the same on any browser.
  4. This course is primarily about the four languages:
    1. HTML describes the contents and structure of a page.
    2. CSS controls the appearance of those contents.
    3. PHP runs on a server to generate HTML in response to inputs.
    4. Javascript runs in a browser to respond quickly to user inputs and modify the page on the fly.
  5. MySQL
    1. MySQL is a popular database system discussed in the text.
    2. We don't plan to cover it due to lack of time.
  6. The Apache Web Server.
    1. The server is the program that receives requests and returns pages. Apache is the make of server we use.
    2. Apache is popular, and was very much top dog for long time. The competition is a bit stiffer these days.