Web Interfaces, Forms & Databases Databases Snyder p HTML Basics Snyder p JavaScript Snyder Chapter 18

Online Resources SQL HTML Forms JavaScript

Concepts A Form is your user interface It includes basic form elements textbox radio buttons check boxes submit buttons etc.

Form Submission Typically, a form must have a submit button But you can configure a form to submit upon hitting enter You can specify an action that will occur if the form is submitted. In this class, we are going to learn about two types of actions.

Form Actions FYI, the method can be “post” or “get,” the only difference is how the information is sent back to the web server. The action is what is most important The action specifies what the form will actually do!

Form Actions Actions call a php, asp, or jsp program (processing done on server) on some servers you can even call a perl program or even a C++ program call a JavaScript function (processing done on client computer, the web browser actually does the processing).

Server-side Processing When your form invokes a php, jsp, or asp program, the web server actually runs the program. What kind of problems could this cause? Why is this necessary?

Power of Server-side Processing A server-side program (a php program for instance) can be very robust. For example, php has the full power of a programming language like C++ has the ability to interface with a database through mysql extentions For example, asp has the full power to interface will all sorts of Microsoft servers and software.

Why Client-Side Processing? Some processing can be done by the client (user’s) computer. Puts less burden on the web server or application server. Quicker response Examples: Flash movies are processed on the client side Form validation can be done client side JavaScript is the leading language used to do client-side processing

Web Interface Problems Typical Computer Interfaces (take Excel for example) can do a lot. The interface is truly dynamic It refreshes constantly It’s installed locally and can use your computer’s full resources. Web Interfaces are intrinsically limited by the Web Browser and because resources aren’t locally available.