Prevent the use of symbols

[eluser]skunkbad[/eluser]
[quote author="nuwanda" date="1290697437"]The simple solution, and the one you should use, is the form validation rule in CI.

http://ellislab.com/codeigniter/user-gui...ation.html

The alpha rule.[/quote]

Of course you should provide form validation, but when a developer becomes lazy and does not provide client side validation of form fields, then the site visitors are inconvenienced with potentially re-submitting a form until they figure out the expected input.