DroidScript

This chapter documents many of the JavaScript language operators, expressions and keywords.

Expressions and operators by category

For an alphabetical listing see the sidebar on the left.

Primary expressions

Basic keywords and general expressions in JavaScript.

function

The function keyword defines a function expression.

[]

Array initializer/literal syntax.

{}

Object initializer/literal syntax.

/ab+c/i

Regular expression literal syntax.

( )

Grouping operator.

Left-hand-side expressions

Left values are the destination of an assignment.

Property accessors

Member operators provide access to a property or method of an object
(object.property and object["property"]).

new

The new operator creates an instance of a constructor.

Increment and decrement

Postfix/prefix increment and postfix/prefix decrement operators.

A++

Postfix increment operator.

A--

Postfix decrement operator.

++A

Prefix increment operator.

--A

Prefix decrement operator.

Unary operators

A unary operation is operation with only one operand.

delete

The delete operator deletes a property from an object.

void

The void operator discards an expression's return value.

typeof

The typeof operator determines the type of a given object.

+

The unary plus operator converts its operand to Number type.

-

The unary negation operator converts its operand to Number type and then negates it.

~

Bitwise NOT operator.

!

Logical NOT operator.

Arithmetic operators

Arithmetic operators take numerical values (either literals or variables) as their operands and return a single numerical value.

+

Addition operator.

-

Subtraction operator.

/

Division operator.

*

Multiplication operator.

%

Remainder operator.

Relational operators

A comparison operator compares its operands and returns a Boolean value based on whether the comparison is true.

in

The in operator determines whether an object has a given property.

instanceof

The instanceof operator determines whether an object is an instance of another object.

<

Less than operator.

>

Greater than operator.

<=

Less than or equal operator.

>=

Greater than or equal operator.

Equality operators

The result of evaluating an equality operator is always of type Boolean based on whether the comparison is true.

==

Equality operator.

!=

Inequality operator.

===

Identity operator.

!==

Nonidentity operator.

Bitwise shift operators

Operations to shift all bits of the operand.

<<

Bitwise left shift operator.

>>

Bitwise right shift operator.

>>>

Bitwise unsigned right shift operator.

Binary bitwise operators

Bitwise operators treat their operands as a set of 32 bits (zeros and ones) and return standard JavaScript numerical values.

&

Bitwise AND.

|

Bitwise OR.

^

Bitwise XOR.

Binary logical operators

Logical operators are typically used with boolean (logical) values, and when they are, they return a boolean value.

&&

Logical AND.

||

Logical OR.

Conditional (ternary) operator

(condition ? ifTrue : ifFalse)

The conditional operator returns one of two values based on the logical value of the condition.

Assignment operators

An assignment operator assigns a value to its left operand based on the value of its right operand.

=

Assignment operator.

*=

Multiplication assignment.

/=

Division assignment.

%=

Remainder assignment.

+=

Addition assignment.

-=

Subtraction assignment

<<=

Left shift assignment.

>>=

Right shift assignment.

>>>=

Unsigned right shift assignment.

&=

Bitwise AND assignment.

^=

Bitwise XOR assignment.

|=

Bitwise OR assignment.

Comma operator

,

The comma operator allows multiple expressions to be evaluated in a single statement and returns the result of the last expression.

 Created by Mozilla Contributors and licensed under CC-BY-SA 2.5