JSHint

Snippet from Wikipedia: JSHint

JSHint is a static code analysis tool used in software development for checking if JavaScript source code complies with coding rules. JSHint was created in 2011 by Anton Kovalyov as a fork of the JSLint project (by Douglas Crockford). Anton and others felt JSLint was getting "too opinionated", and did not allow enough customization options. The JSHint maintainers publish both an online version, and a command-line version.

The online version is accessible through the official website in which users can paste code to run the application online. The command-line version of JSHint (distributed as a Node.js module), enables automated linting processes by integrating JSHint into a project's development workflow.