1. Internet Applications Notes for Chapter 19 Digital Domain, 2 ed

2. E-Commerce E-Commerce is rapidly emerging as an essential business strategy E-Commerce has the following components Web interface on the client side backend databases on the server side scripts to enable the interaction of these two

3. Client-Side Scripting in E-Commerce Resides on the client machine (downloaded with the Web interface) Creates client interactivity Collects data from the user Does preliminary analysis and validation on user- supplied data Sends validated data to the server

4. Server-Side Scripting in E-Commerce Resides on the server Accepts data from the client Uses that data to search backend databases write to databases initiate credit card processes, etc. Returns response data to the client

5. Client-Side Processing and DHTML Dynamic HTML (DHTML) is a collection of technologies to make client-side interactions better and more interactive is a bit of a misnomer – it is not an extension of HTML DHTML is not standardized different browser companies compete with their own DHTML features as long as the “browser wars” persist, DHTML is unlikely to be standardized Two important components of DHTML CSS (cascading style sheets) client-side scripting

6. Cascading Style Sheets (CSS) Define styles for formatting and displaying information provides for better Web site internal consistency makes Web site style modifications much easier Three types of CSS inline embedded external applied with precedence: inline->embedded->external

7. Client-Side Scripting and Forms Scripting works hand-in-hand with HTML forms HTML forms have built-in mechanisms for soliciting and collecting user data Forms are a part of standard HTML Client-side scripts are used to take action on the data collected before sending it to the server Such scripts are invoked using the onSubmit event handler

8. Server-Side Scripting Accepts data from client Often written in CGI (Common Gateway Interface) actually an interface rather than a scripting language can be written in a number of different scripting languages PHP: HyperText Preprocessor ASP (Active Server Pages – Microsoft)

9. Java Programming Java is an object-oriented full-purpose (as opposed to scripting only) programming language Java is noted for its excellent cross-platform capability accomplished by first compiling into bytecodes bytecodes are machine-independent a given machine’s Java RTE (Runtime Environment) then interprets the bytecodes into the appropriate machine language at run-time Java applets are small Java programs designed specially for the Web

10. XML (eXtensible Markup Language) XML is a very flexible language designed to facilitate exchange of information across the Web It is actually a meta-language that allows the creation of domain specific markup languages HTML is but one example of a language that could be created with XML Languages especially designed for the exchange of financial information, medical information, graphical information, and mathematics are other examples of existing XML specifications

11. Summary E-Commerce is rapidly emerging as an essential business strategy E-Commerce has the following components Web interface on the client side backend databases on the server side scripts to enable the interaction of these two Client-side scripts create client interactivity collect data from the user send data to the server Server-side scripts accept data from the client use that data to access backend databases or other server resources return response data to the client

12. Summary (cont’d) Dynamic HTML (DHTML) is a collection of technologies to improve client-side interactivity and Web site usability two important components of DHTML CSS (cascading style sheets) client-side scripting scripting works hand-in-hand with HTML forms Java is an object-oriented full-purpose (as opposed to scripting only) programming language Java applets are small Java programs designed specially for the Web

13. Summary (cont’d) XML is a meta-language that allows the creation of domain specific markup languages It is designed to facilitate exchange of information across the Web