Web Interfaces, Forms &Databases

Databases Snyder p351-389

HTML Basics Snyder p89-115

JavaScript Snyder Chapter 18

Online Resources

SQL http://www.sql.org/

HTML Formshttp://www.w3schools.com/html/html_forms.asp

JavaScripthttp://www.w3schools.com/js/js_intro.asp

Concepts

A Form is your user interface

It includes basic form elementstextbox

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

<form method="post" action="insert.php">

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<form method="post" action="insert.php">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, asphas 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 responseExamples:

Flash movies are processed on the client sideForm 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 limitedby the Web Browser

and because resources aren’t locally available.