1. Web Concepts
Lesson 2
ITBS2203 E-Commerce for IT

2. A global network that is based on the Internet
What is Web?
A global network that is based on the Internet
ITBS2203 E-Commerce for IT

3. What is Web server?
It is a computer/machine (hardware) that hosts web sites and software that runs on such a machine and processes requests from Web browsers which is called web client software.
ITBS2203 E-Commerce for IT

4. Functions of the Web Server
It must run continually and must always be ready to respond to the requests of the client
It must be able to serve more than one client at a time.
It stores text, images, audio, video and other shared elements
The various processes have to be able to connect to each other and exchange information
ITBS2203 E-Commerce for IT

5. Most Popular Web Servers
Apache web server
HTTP web server
Microsoft Internet Information Services (IIS)
Windows server
Apache Tomcat
Developed to support servlets and JSP scripts.
ITBS2203 E-Commerce for IT

6. What is Web Browser
It is a computer program (software) that is used for viewing web sites and web pages whether you use a desktop computer, a laptop or even a mobile device such as your cell phone.
ITBS2203 E-Commerce for IT

7. Most Popular Web Browsers
Chrome
Microsoft Internet Explorer
Firefox
Opera
Apple’s Safari
ITBS2203 E-Commerce for IT

8. What is HTTP Protocol?
It has a set of instructions for accurate information exchange.
ITBS2203 E-Commerce for IT

9. HTTP Client Methods – GET and POST
The GET Method
The GET method is used to retrieve web pages from the web server.
It is a part of the request line from the client and tells the server to pass a copy of the document back to the browser.
The POST Method
Data from the POST method is sent by the client as a part of the request body.
The server receives this data and sends it to a PHP parser along with other variables.
The HEAD Method
It is used to find information about a document located on the server not retrieve it.
It is very similar to the GET method except no data is returned by the server.
ITBS2203 E-Commerce for IT

10. Client-Side Scripting Languages or Technologies
Scripting Languages or Technologies include: 
HTML, DHTML, CSS, JavaScript, VB Script (Visual Basic Script) Java applets...
Browser plug-ins: Java, Flash, Shockwave, Quicktime, Silverlight etc...
Advantages
Disadvantages
Processing done by the web browser
There is no database access! 
Fast
Cannot depend upon client-side code
Minimal demands on server : files are downloaded to client for execution
Browser dependency
Different browsers have different behaviors
Browser plug-ins man not be installed: Flash, Java, Shockwave
ITBS2203 E-Commerce for IT