JavaScript
Tutorials
Complete beginners
1. JavaScript basics
2. JavaScript first steps
3. JavaScript building blocks
4. Introducing JavaScript objects
JavaScript Guide
1. Introduction
2. Grammar and types
3. Control flow and error handling
4. Loops and iteration
5. Functions
6. Expressions and operators
7. Numbers and dates
8. Text formatting
9. Regular expressions
10. Indexed collections
11. Keyed collections
12. Working with objects
13. Using classes
14. Using promises
15. Iterators and generators
16. Meta programming
17. JavaScript modules
Intermediate
Advanced
References
Built-in objects
Expressions & operators
Statements & declarations
Functions
Classes
Errors
1. Overview
2. Error: Permission denied to access property "x"
3. InternalError: too much recursion
4. RangeError: argument is not a valid code point
5. RangeError: BigInt division by zero
6. RangeError: BigInt negative exponent
7. RangeError: invalid array length
8. RangeError: invalid date
9. RangeError: precision is out of range
10. RangeError: radix must be an integer
11. RangeError: repeat count must be less than infinity
12. RangeError: repeat count must be non-negative
13. RangeError: x can't be converted to BigInt because it isn't an integer
14. ReferenceError: "x" is not defined
15. ReferenceError: assignment to undeclared variable "x"
16. ReferenceError: can't access lexical declaration 'X' before initialization
17. ReferenceError: deprecated caller or arguments usage
18. ReferenceError: reference to undefined property "x"
19. SyntaxError: "0"-prefixed octal literals and octal escape seq. are deprecated
20. SyntaxError: "use strict" not allowed in function with non-simple parameters
21. SyntaxError: "x" is a reserved identifier
22. SyntaxError: a declaration in the head of a for-of loop can't have an initializer
23. SyntaxError: applying the 'delete' operator to an unqualified name is deprecated
24. SyntaxError: cannot use `??` unparenthesized within `||` and `&&` expressions
25. SyntaxError: for-in loop head declarations may not have initializers
26. SyntaxError: function statement requires a name
27. SyntaxError: identifier starts immediately after numeric literal
28. SyntaxError: illegal character
29. SyntaxError: invalid assignment left-hand side
30. SyntaxError: invalid BigInt syntax
31. SyntaxError: invalid regular expression flag "x"
32. SyntaxError: JSON.parse: bad parsing
33. SyntaxError: Malformed formal parameter
34. SyntaxError: missing ; before statement
35. SyntaxError: missing : after property id
36. SyntaxError: missing ) after argument list
37. SyntaxError: missing ) after condition
38. SyntaxError: missing ] after element list
39. SyntaxError: missing } after function body
40. SyntaxError: missing } after property list
41. SyntaxError: missing = in const declaration
42. SyntaxError: missing formal parameter
43. SyntaxError: missing name after . operator
44. SyntaxError: missing variable name
45. SyntaxError: redeclaration of formal parameter "x"
46. SyntaxError: return not in function
47. SyntaxError: test for equality (==) mistyped as assignment (=)?
48. SyntaxError: Unexpected '#' used outside of class body
49. SyntaxError: Unexpected token
50. SyntaxError: unparenthesized unary expression can't appear on the left-hand side of '**'
51. SyntaxError: unterminated string literal
52. SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead
53. TypeError: 'x' is not iterable
54. TypeError: "x" has no properties
55. TypeError: "x" is (not) "y"
56. TypeError: "x" is not a constructor
57. TypeError: "x" is not a function
58. TypeError: "x" is not a non-null object
59. TypeError: "x" is read-only
60. TypeError: can't assign to property "x" on "y": not an object
61. TypeError: can't convert BigInt to number
62. TypeError: can't convert x to BigInt
63. TypeError: can't define property "x": "obj" is not extensible
64. TypeError: can't delete non-configurable array element
65. TypeError: can't redefine non-configurable property "x"
66. TypeError: cannot use 'in' operator to search for 'x' in 'y'
67. TypeError: cyclic object value
68. TypeError: invalid 'instanceof' operand 'x'
69. TypeError: invalid Array.prototype.sort argument
70. TypeError: invalid assignment to const "x"
71. TypeError: More arguments needed
72. TypeError: property "x" is non-configurable and can't be deleted
73. TypeError: Reduce of empty array with no initial value
74. TypeError: setting getter-only property "x"
75. TypeError: X.prototype.y called on incompatible type
76. URIError: malformed URI sequence
77. Warning: -file- is being assigned a //# sourceMappingURL, but already has one
78. Warning: 08/09 is not a legal ECMA-262 octal constant
79. Warning: Date.prototype.toLocaleFormat is deprecated
80. Warning: expression closures are deprecated
81. Warning: String.x is deprecated; use String.prototype.x instead
82. Warning: unreachable code after return statement
Misc

Division assignment (/=)

Try it

Syntax

Examples

Using division assignment

Specifications

Browser compatibility

See also