Douglas Crockford's Javascript syntax checker, JSLint, has served the community well, but is opinionated and inflexible. If you program Javascript and omit unnecessary semicolons, for example, JSLint will continually badger you about your style choice.
node.js
Semicolon-Agnostic Javascript Syntax Checking with JSHint
Submitted by Mike on Sun, 2011-03-27 06:36Talk: Introduction to Node.js from a Drupal Dev's Perpsective
Submitted by Mike on Thu, 2010-11-25 22:59Not Only Drupal: Using Drupal to Manage Data for JS/SSJS Apps
Submitted by Mike on Mon, 2010-10-04 05:23I gave a talk today at the 2010 Pacific Northwest Drupal Summit on using Drupal as a datastore for Javascript applications.
You can check out the slides on Slideshare or download the PDF [22 MB].
