Many JavaScript implementations do not warn against questionable coding practices. Yes, that's nice for the site that "works best with Internet Explorer" (designed with templates, scripted with snippets copied from forums). But it's a nightmare when you actually want to write quality, maintainable code.

That's where JavaScript Lint comes in. With JavaScript Lint, you can check all your JavaScript source code for common mistakes without actually running the script or opening the web page.

JavaScript Lint holds an advantage over competing lints because it is based on the JavaScript engine for the Firefox browser. This provides a robust framework that can not only check JavaScript syntax but also examine the coding techniques used in the script and warn against questionable practices.