One thing I have always disliked doing is using JavaScript to validate forms client-side.  I found it bulky, ugly, and unappealing from the user's vantage point.  Having recently discovered the powerful JQuery library, I figured there must be a JQuery solution that could be used to address my concerns with classic JavaScript validation.

That is when I found this JQuery Validation library.  It is easy to use and comes with an ample amount of demos.  There are also some good demos in the documentation page which demonstrate how to validate various controls.

Of course, to use this, you will need the JQuery library in your project.

The only thing I could not determine was how to do some advanced validation:  namely, avoiding validation on controls that were part of a panel that was not visible.  For example, I have a form that allows a user to make donations and to select a payment method; cheque or credit card.  When the cheque panel is visible (thus the credit card panel is not), I don't want validation on the controls on the credit card panel.  The solution to thus turned out to be quite easy