"But doesn't j Query make it easy to write your own validation plugin?" Sure, but there are still a lot of subtleties to take care of: You need a standard library of validation methods (such as emails, URLs, credit card numbers).

This particular one is one of the oldest j Query plugins (started in July 2006) and has proved itself in projects all around the world.

There is also an article discussing how this plugin fits the bill of the should-be validation solution. Have a look at this example: A single line of j Query to select the form and apply the validation plugin, plus a few annotations on each element to specify the validation rules.

Of course that isn't the only way to specify rules.

You also don't have to rely on those default messages, but they come in handy when starting to setup validation for a form.

That behaviour can be irritating when clicking through demos of the validation plugin – it is designed for an unobtrusive user experience, annoying the user as little as possible with unnecessary error messages.

So when you try out other demos, try to react like one of your users would, and see if the behaviour is better then.

If not, please let me know about any ideas you may have for improvements! Throughout the documentation, two terms are used very often, so it's important that you know their meaning in the context of the validation plugin: The validate method returns a Validator object that has a few public methods that you can use to trigger validation programmatically or change the contents of the form.

You may need different ways to specify validation rules according to the server-side enviroment you are using on different projects.

And after all, you don't want to reinvent the wheel, do you?