JavaScript and Web Application Client Engineering
Modern web applications leverage client-side JavaScript to provide a richer and more responsive experience for end users. We bring the same level of discipline (architecture, design, testing) to front-end code running in the browser as we do to back-end code running in an application server.
There are a number of robust and widely used JavaScript frameworks to provide this interactive "AJAX"-style functionality. We use and recommend the Yahoo! User Interface Library, (commonly known as YUI) where possible, but we have experience with several of the other top-shelf JavaScript libraries if your needs are not consistent with YUI's capabilities.
While JavaScript-enabled applications push the envelope of what can be done in a browser-based applicaiton, we temper our enthusiasm with a healthy dose of paranoia and engineer your end-to-end solution with the expectation that bad guys will try to sidestep or exploit any business logic that gets evaluated in the browser. You could say that we take a "belt-and-suspenders" approach to safeguarding the integrity of your data by ensuring server-side validation of critical business rules, especially in applications that are exposed to the Internet. This allows you to sleep soundly while still providing your user base with a snappy, responsive application.