Web Core-Technologies

alright so im beginning to learn about publishing on the web using core technolgies:

seems there are 7 core technologies:

1. XHTML is a mark up language. it has some control tags and content.

control tags used by browser to render the document on the web page. my question, how do control tags help render documents on the clinet monitor?

you can write the control tags by hand, or you can also use xhtml editors like MSFT FrontPage and Dreamweaver . the W3C has provided spcification for this language

2. Cascading Style Sheets

so CSS specifies how content is to be displayed. The trend in web design has been to seperate content from rendering instructions.

seperate content from rendering instructions...this is CSS

3.XML

stands for eXtensible Markup language. so i can create my own control tags. xml you can have any number of control tags, the tags can be used to describe content of the doc for humans and machines.

4. JavaScript

is a scripting language. used to write scripts that run on the client side.

ususally used in forms, they do the client side verification of data you enter in those forms. the scripts can also be used with CSS to produce dynamic effects. these are called Dynamic HTML

5. Java

is an object oriented language that is used for writing applets

Current Trends in Web Programming

Rich User Experience:

most wbe applications are not as responsive as desktop applications because they run on the server side.

AJAX has solved with problem. It stands for Asynchronous JavaScript and XML. SO! it means that small data can be transfered between client and server without web page having to be loaded

Web Server: is a software program that provides documents to browsers. Apache is widely used in this regard=68% of the market share.

A web browser inititates a request with a server, by sending it the URL of the document it wants...the server searches for it and restrives the document (but where does it search for it, in a database?)

so the internet has many layers.

i think important to me is TCP and Application Layer

in the application layer you have: SMTP and HTTP

so you have SMTP stands for simple mail transfer protocol

does the POP

and the IMAP

HTTP (hyper text transfer protocol)

transfers web pages from server to the client

A browser is an HTTP client for HTTP servers (listens on port 80)

http is the protocol for transfering files through TCP/IP sockets

so URL's are

universal resource locators, used to identify documents in the internet

they have the following patter:

scheme:object-address

in the case of HTTP:

//fully qualified domain name/path to document

Domain Names

okay so Overview of the internet chapter on Mitra's website was a wee bit confusing. I think seeing it in action would help me understand better

so there is HTTP, Domain names, IP address, DNS

Are URL's IP addresses which DNS serves up?

internet uses all the protocols

the web refers to http

i guess that's the most important thought. no one uses email anymore

most requests on the internet are for existing documents, but some requests are for program execution

browsers always inititate,

servers always react, although sometimes servers require responses and recall that facebook chat has the client wait and when the server gets a message can push to the client