Web Concepts Lesson 2 ITBS2203 E-Commerce for IT

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

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

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

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

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

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

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

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

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