JavaScript Reference


A block statement is used to group zero or more statements. The block is delimited by a pair of curly brackets.
Terminates the current loop, switch, or label statement and transfers program control to the statement following the terminated statement.
Declares a read-only, named constant.
Terminates execution of the statements in the current iteration of the current or labelled loop, and continues execution of the loop with the next iteration.
Invokes any available debugging functionality. If no debugging functionality is available, this statement has no effect.
Creates a loop that executes a specified statement until the test condition evaluates to false. The condition is evaluated after executing the statement, resulting in the specified statement executing at least once.
Allows a signed script to provide properties, functions, and objects to other signed or unsigned scripts. This feature is not in ECMA-262, Edition 3.
Creates a loop that consists of three optional expressions, enclosed in parentheses and separated by semicolons, followed by a statement executed in the loop.
Iterates over the enumerable properties of an object, in arbitrary order. For each distinct property, statements can be executed.
Iterates over iterable objects (including arrays, array-like objects, iterators and generators), invoking a custom iteration hook with statements to be executed for the value of each distinct property.
Iterates a specified variable over all values of object's properties. For each distinct property, a specified statement is executed.
Declares a function with the specified parameters.
Executes a statement if a specified condition is true. If the condition is false, another statement can be executed.
Allows a script to import properties, functions, and objects from a signed script that has exported the information.
Provides a statement with an identifier that you can refer to using a break or continue statement.
Declares a block scope local variable, optionally initializing it to a value.
Specifies the value to be returned by a function.
Evaluates an expression, matching the expression's value to a case label, and executes statements associated with that case.
Throws a user-defined exception.
Marks a block of statements to try, and specifies a response, should an exception be thrown.
Declares a variable, optionally initializing it to a value.
Creates a loop that executes a specified statement as long as the test condition evaluates to true. The condition is evaluated before executing the statement.
Extends the scope chain for a statement.

Operators and other keywords

Arithmetic Operators

(+, -, *, /, %, ++, --, unary -, unary +)

Assignment Operators

(=, *=, /=, %=, +=, -=, <<=, >>=, >>>=, &=, ^=, |=)

Bitwise Operators

(&, |, ^, ~, <<, >>, >>>)

Comparison Operators

(==, !=, ===, !==, >, >=, <, <=)

Logical Operators

(&&, ||, !)

String Operators

(+ and +=)

Member Operators

( and object["property"])

Special Operators
Conditional Operator

(condition ? ifTrue : ifFalse)

Comma Operator


delete Operator


function Operator


get Operator


in Operator


instanceof Operator


let Operator


new Operator


set Operator


this Operator


typeof Operator


void Operator


yield Operator


Operator Precedence
Operator precedence defines the order in which operators are evaluated.


E4X (extension)

Global statements:

Global functions:

Global constructors:

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