Errors

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!

• Error: Permission denied to access property "x"
• InternalError: too much recursion
• RangeError: argument is not a valid code point
• RangeError: invalid array length
• RangeError: precision is out of range
• RangeError: radix must be an integer
• RangeError: repeat count must be less than infinity
• RangeError: repeat count must be non-negative
• ReferenceError: "x" is not defined
• ReferenceError: assignment to undeclared variable "x"
• ReferenceError: deprecated caller or arguments usage
• ReferenceError: invalid assignment left-hand side
• ReferenceError: reference to undefined property "x"
• SyntaxError: "use strict" not allowed in function with non-simple parameters
• SyntaxError: "x" is not a legal ECMA-262 octal constant
• SyntaxError: JSON.parse: bad parsing
• SyntaxError: Malformed formal parameter
• SyntaxError: Unexpected token
• SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead
• SyntaxError: missing ) after argument list
• SyntaxError: missing ; before statement
• SyntaxError: missing ] after element list
• SyntaxError: missing } after property list
• SyntaxError: redeclaration of formal parameter "x"
• SyntaxError: return not in function
• SyntaxError: test for equality (==) mistyped as assignment (=)?
• SyntaxError: unterminated string literal
• TypeError: "x" has no properties
• TypeError: "x" is (not) "y"
• TypeError: "x" is not a constructor
• TypeError: "x" is not a function
• TypeError: "x" is read-only
• TypeError: More arguments needed
• TypeError: invalid Array.prototype.sort argument
• TypeError: property "x" is non-configurable and can't be deleted
• TypeError: variable "x" redeclares argument
• Warning: -file- is being assigned a //# sourceMappingURL, but already has one
• Warning: JavaScript 1.6's for-each-in loops are deprecated
• Warning: unreachable code after return statement

See also

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