JavaScript error reference

Below, you'll find a list of errors which are thrown by JavaScript. These errors can be a helpful debugging aid, but the reported problem isn't always immediately clear. The pages below will provide additional details about these errors. Each error is an object based upon the Error object, and has a name and a message.

Errors displayed in the Web console may include a link to the corresponding page below to help you quickly comprehend the problem in your code.

List of errors

In this list, each page is listed by name (the type of error) and message (a more detailed human-readable error message). Together, these two properties provide a starting point toward understanding and resolving the error. For more information, follow the links below!

• ReferenceError: "x" is not defined
• TypeError: "x" is (not) "y"
• TypeError: "x" is not a function
• Warning: unreachable code after return statement
• Синтаксическая ошибка: пропущенный символ ")" после списка аргументов

See also

• What went wrong? Troubleshooting JavaScript: Beginner's introductory tutorial on fixing JavaScript errors.