Update (1 Feb 2013): I’ve updated the script here, primarily to jump to the latest version of the bassistance plugin.
This article will teach you how to add validation to your WordPress comment forms, using jQuery.
With validation, users can submit their comment and instantly see if they’ve hit an issue. There is no need to submit the page and get WordPress’ default “There is a problem…” page. Instead, errors are displayed inline instantly.
In our example, we will build a plugin which you can drop into any theme and will work instantly.