how to validate a registration page at client side

[eluser]Unknown[/eluser]
i want to validate my registration page at client side . my registration page consisting of
username,
password,
emailid,
phoneno,
address

how to validate each of it
please any one help me

[eluser]bigtony[/eluser]
Have you considered reading the [url="http://ellislab.com/codeigniter/user-guide/libraries/form_validation.html"]Form Validation[/url] page of the User Guide?

[eluser]rogierb[/eluser]
Use javascript to validate client side.

Try http://www.google.com/search?q=validate+...javascript
There are plenty of examples out there

[eluser]bigtony[/eluser]
[quote author="rogierb" date="1253115677"]Use javascript to validate client side.

Try http://www.google.com/search?q=validate+...javascript
There are plenty of examples out there[/quote]
But be aware that hackers can easily bypass client side validation, so server validation is much more secure. But you can still use client side checking with javascript as well for other reasons (e.g. capturing errors early to reduce server load).

[eluser]n0xie[/eluser]
[quote author="bigtony" date="1253116075"]
But be aware that hackers can easily bypass client side validation[/quote]
All you need to do is disable javascript support in your browser. No 'hacking' required ;-)

[eluser]8th wonder[/eluser]
use form validation on codeigniter,
you can also learn JAVASCRIPT it is also best.

[eluser]brianw1975[/eluser]
You could also do what appears to be client side validation with AJAX methods -- this is especially useful for verifying unique usernames/email addresses.

But make no mistake, server side validation cannot be replaced with client side validation.