as I needed client-side form validation, I wrote an extension and thought that maybe it could be useful to others.
This extension uses the Validate JQuery plugin and does nothing but turn yii built-in rules into other rules supported by this (excellent) JQuery plugin.
The work to use client-side validation on existing forms is minimal : replace calls to Yii CHtml helpers methods (like activeTextField) with calls to the same method implemented by the extension. Call endForm() at the end, and that's it.
I've not wrapped all CHtml helpers method and not all Yii built-in rules are supported, but that's just a first release and if it is intresting for others, I'll implement what is missing. I strongly encourage you to take a look to the readme file for more info.
Ok, so try it and play with the samples included in the zip... tell me what you think : every feedback is very welcome