JSLint is a JavaScript program that looks for problems in JavaScript programs. It is a code quality tool, and it gonna hurt you... 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 defines a professional subset of JavaScript, a stricter language than that defined by Third Edition of the ECMAScript Programming Language Standard. The subset is related to recommendations found in Code Conventions for the JavaScript Programming Language. JavaScript is a sloppy language, but inside it there is an elegant, better language. JSLint helps you to program in that better language and to avoid most of the slop. JSLint will reject programs that browsers will accept because JSLint is concerned with the quality of your code and browsers are not. You should accept all of JSLint's advice.