Client-Side Validation with Javascript

1. Client-Side Validation with Javascript by Daniel Yee

2. Client-Side Scripting Language • Javascript • European Computer Manufacturers Association (ECMA) • ECMA-262 • Third edition • Updated Last December 1999

3. Javascript • Not a full fledged programming language • Cannot connect to databases • Limited interactions to system resources • Cannot do tasks most web databases require

4. Common Uses of Javascript • Validation of <form> data • Simple interaction with <form> data • Adding dynamic elements to web page

5. 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”>

6. 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

7. Validating <form> Data • Simple example for validating a <form> with JavaScript • Check for whitespace

8. Batch Error Reporting • Validation for multiple fields • Batch error reporting • Example

9. Interactive Validation • Password <form> validation • Example

10. Dynamic Elements • Some implementations not associated with web database applications • MouseOver • Prefilled calculations

11. MouseOver • Creating a mouseOver Event • Example

12. Prefilled Calculations • Shopping cart updating • Example

13. 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

14. REMEMBER!!!!! • NEVER USE AS THE ONLY METHOD TO ENSURE REQUIREMENTS, SECURITY, AND CONSTRAINTS • WHY? • BECAUSE IT CAN BE BYPASSED BY THE USER

15. The End