16 terms

Web Technologies

World Wide Web Players
The documents
The servers
the consumers
the delivery method
The Document
The document is the data that is to be presented to the consumer or in other words the content of the Internet
HTML is a simple language that uses tags embedded within the text of a document to control how the document is displayed.

HTML files are text files that can be created in notepad
XHTML is a language/protocol that reformulates HTML into XML.
The Server
There are many types of servers
-Hyper Text Transfer Protocol (HTTP)
-File Transfer Protocol (FTP)
-Simple Mail Transfer Protocol (SMTP)
-Post Office Protocol (POP)
Server Duties
-Store documents
-Deliver document to requesting clients
-Secure documents
The Consumer
The client software is the software that the end-user uses to access information on the web

Some examples of client software are:
-Web browsers such as Internet Explorer and Firefox (HTTP) (FTP)
-WS-FTP or SmartFTP (FTP)
-Mail software such as Microsoft Outlook, or Mozilla Thunderbird (POP3) (SMTP)
-Media players such as Real Player (RealAudio), VLC, etc.
Client Software Duties
Request documents
Decode documents
Display documents to the user
The Delivery
The delivery method is the set of rules that allow a server to send the content of a document to the client. The rules are the delivery protocol. There are many protocols on the internet. The typical method for delivering HTML documents is via the Hyper Text Transfer Protocol (HTTP) or the encrypted version HTTPS
HTTP is a protocol that was designed to deliver HTML content to web browsers
HTTP can be used to
-Request information about the sever
-Request documents from the server
-Send documents to the server
-Delete documents from the server
HTTP Communications
When a HTTP client connects to a HTTP server the two communicate via a simple set of request and response messages. Clients send requests to the server and the server sends responses back
Uniform Resource Identifier/Uniform Resource Locator
Contains the protocol, server, port number, the path to the document to retrieve, and the query
HTTP Request
URI is converted into appropriate HTTP request command

HTTP Response
The HTTP server will respond to the client's request with a response that contains headers that identify features of the document
HTTP Commands
GET-retrieves doc
HEAD-requests just header info
POST-sends data from client to server
PUT-places doc on server
DELETE-deletes doc from server
Response Status
100-199: Informational
200-299:Client request successful
300-399:client request redirected
400-499:client request incomplete
500-599:server error