JSLint : Static program analysis tool

JSLint is a static program analysis tool. It was developed by Douglas Crockford. Static program analysis is the interpretation of computer software that is performed with actually executing. JSLint is used for checking if JavaScript source code complies with coding rules.It can be referred as code quality tool.

JavaScript is a young-for-its-age language. It was originally intended to do small tasks in webpages, tasks for which Java was too heavy and clumsy. But JavaScript is a surprisingly capable language, and it is now being used in larger projects. Many of the features that were intended to make the language easy to use are troublesome when projects become complicated. A lint for JavaScript is needed: JSLint, a JavaScript syntax checker and validator.

JSLint takes a JavaScript source and scans it. If it finds a problem, it returns a message describing the problem and an approximate location within the source. The problem is not necessarily a syntax error, although it often is. JSLint looks at some style conventions as well as structural problems. It does not prove that your program is correct. It just provides another set of eyes to help spot problems.

JSLint is provided primarily as an online tool, but there are also command-line adaptations. JSLint.VS2012 extension also available for Microsoft Visual Studio 2012.
Also, JSONLint is the JSON validator availabe for online use.

Links:
http://www.jslint.com/
http://visualstudiogallery.msdn.microsoft.com/1a417c37-4d6f-43ca-b753-6ea6eb5041fd
http://jsonlint.com/

JSLint.NET
JSLint.NET is a wrapper for Douglas Crockford's JSLint, the JavaScript code quality tool. It can validate JavaScript anywhere .NET runs.
At it's core, the JSLint.NET project aims to provide:

• a complete, accurate and up-to-date wrapper for JSLint
• an interface that's natural for .NET developers while staying true-to-source
• a suite of valuable tools that assist JavaScript developers working on Microsoft platforms

Links:
http://jslintnet.codeplex.com/