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