Client-Side Validation with Javascript

by

Daniel Yee

Client-Side Scripting Language

• Javascript

• European Computer Manufacturers Association (ECMA)

• ECMA-262

• Third edition

• Updated Last December 1999

Javascript

• Not a full fledged programming language

• Cannot connect to databases

• Limited interactions to system resources

• Cannot do tasks most web databases require

Common Uses of Javascript

• Validation of <form> data

• Simple interaction with <form> data

• Adding dynamic elements to web page

Benefits of using Javascript

• Faster response then using server-side validation

• Reduction in web-server load

• Reduction in network traffic

• Can be saved as a file - file.js and reused by typing <script type= text/javascript src=“file.js”>

Warning!!!!!!!!!!!!!

• Never rely on client-side validation as the only method of ensuring requirements and constraints

• Javascript can be bypassed by the user through design, error, or configuration

Validating <form> Data

• Simple example for validating a <form> with JavaScript

• Check for whitespace

Batch Error Reporting

• Validation for multiple fields

• Batch error reporting

• Example

Interactive Validation

• Password <form> validation

• Example

Dynamic Elements

• Some implementations not associated with web database applications

• MouseOver

• Prefilled calculations

MouseOver

• Creating a mouseOver Event

• Example

Prefilled Calculations

• Shopping cart updating

• Example

Conclusion

• Javascript is a client-side scripting language

• Can be used for validating forms and enhancing user interactions

• Benefits include improved speed, reduced load, and added features

REMEMBER!!!!!

• NEVER USE AS THE ONLY METHOD TO ENSURE REQUIREMENTS, SECURITY, AND CONSTRAINTS

• WHY?

• BECAUSE IT CAN BE BYPASSED BY THE USER

The End