JSLint has saved me many hours in the past. (I tend to hose JS's camel spelling, especially since I rarely use JS in my primary endeavors.) However, it is one of those online tools of which I spoke. While that is usually acceptable for me, this young couple is on a data-capped connection, so online services are, for the most part, anathema to them. (JSLint also, the last time I used it, has trouble with included .js files - cannot see a directory structure on a local drive, so it cannot detect the almost inevitable path errors/typos.)