Unit 1 – Internet Basics

Presentation 4

Web Programming

Objectives

At the end of this presentation, you will be able to

• Use the browser

• Discuss about Web server

• Discuss about data transfer from client to server.

• Identify parts of IP address and URL.

The Browser

• Software that acts as an interface between the user and the Web.

• Resides in the client machine.

• Reads the instructions given in a language such as HTML and displays the document in the browser window.

The Browser

• Eg. Internet Explorer, Netscape Navigator, Hot Java, Mozilla, Mosaic and Opera.

The Internet Explorer

• To open the Internet Explorer select Start Programs Internet Explorer.

• Title bar is displayed at the top

The Internet Explorer

• Menu bar is displayed below the title bar.

• Below the Menu bar is the Standard Buttons toolbar.

The Internet Explorer

• Next to the Standard Buttons toolbar is the Address bar. The URL of a Web page is typed here.

• Below the address bar is the area where the document will be displayed.

The Internet Explorer

• Below the address bar is the area where the document will be displayed.

• The status bar is displayed at the bottom of the Internet Explorer window.

Opening a Web page

• Type the URL of the Web page in the Address bar.

• Press the Enter key.

• Eg. Open yahoo.com by typing www.yahoo.com in the Address bar and press the Enter key.

Buttons in the Standard buttons toolbar

- To open the previous page that had been visited.

- To open the next page to the current page that had been visited.

- To stop the search in the middle.

- To restart the search from the beginning.

Buttons in the Standard buttons toolbar

- Web pages that you often visit can be stored in Favorites.

- Clicked to get back to the home page set in the browser.

Web Server

• Client computer makes request.• Server Computer responds to client’s request.• Some of the servers are Web server, FTP

server and mail server.• Web server follows a set of rules while

communicating with the client known as HTTP (Hypertext Transfer Protocol).

Steps that occur while opening a Web page

1. Browser breaks the URL into different parts namely, the protocol (HTTP – Hypertext Transfer Protocol), the server name and the file name.

Protocol

Server Name

http://www.geographia.com/indx04.htm

File Name

Steps that occur while opening a Web page

• Sends the server name to a name server.

• Name server translates Server name into IP address.

Steps that occur while opening a Web page

• Sends the server name to a name server.

• Browser uses Server name and sends a GET request to the server asking for the Web page.

Steps that occur while opening a Web page

• Server finds the requested page and sends HTML code of the page to the browser.

• Browser reads the HTML code and displays the page in the browser window.

Data Transmission in the Internet

IP Address

• Computer in the network is identified by a unique address known as IP address.

• It contains four parts each called octet. • Each octet made up of 8 bits (8 binary

digits) and makes a total of 4 X 8 = 32 bits.

103.38.123.214

Represents a network

Represents a specific computer in the network

IP Address

• Each octet is a number between 0 and 255 in decimal form and is separated by a dot.

• First 3 octets represent the network to which the computer is connected.

• Fourth octet represents the computer in that network.

103.38.123.214

Represents a network

Represents a specific computer in the network

URL

• Every Web page in WWW has a unique address called as URL

• Similar to the postal address. • URL contains protocol, domain name, path

and Web page name.

Protocol

Server Name

http://www.geographia.com/indx04.htm

File Name

URL

• Last portion in the domain name is called top-level domain that represents the type of organization, the Web site belongs to.

Top-Level Domains

Domain Type

com Commercial Organizations and companies

org Non-Profit Organizations

net Company that provides network

gov Government Organizations

edu Educational Institutions

Summary

In this presentation, you learnt the following:• Open the Internet Explorer by selecting

Start Programs Internet Explorer • Browser is an application program that

displays the content of a web Page.• Some of the servers are Web server, FTP

server and mail server.

Summary

In this presentation, you learnt the following:• Each computer in the network is identified

by a unique address known as IP address.• Every Web page in WWW has a unique

address called as URL.

Assignment

1. Write how to open Internet Explorer.

2. Define Web browser.

3. Give some examples of Web browser.

4. Name the different parts of a URL.

5. Define IP Address.