Expressions and Operators

Expressions and operators in JavaScript follow closely their cousins in C/C++ or Java. Users familiar with these languages should feel right at home.

Expressions are combinations of variables and operators to produce a resulting value. Expressions can be used as the right hand side of an assignment, as function arguments, and in return statements. Expressions are the heart of JavaScript.

Embedded JavaScript implements a subset of the ECMAScript specification for expressions and operators. The following operators are not supported: ===, !==, >>>, prefix ++ and --, &, |, ^, ?:. The operator / assignment combinations such as *= are also not supported.

Operator Summary

The following table summarises the operators available in Embedded JavaScript. For a complete specification, please consult the ECMA-262 specification.

Operator	Operands	Description
*  /  %	Numbers	Multiply, divide, modulo
+	Numbers, Strings	Add numbers, catenate strings
-	Numbers	Subtract numbers
!	Boolean	Unary not
++	Numbers	Post-increment number
--	Numbers	Post-decrement number
<<	Integers	Left shift
>>	Integers	Right shift
==  !=	All	Compare if equal, not equal
<  <=	Numbers, Strings	Compare if less than, less than or equal
>  >=	Numbers, Strings	Compare if greater than, greater than or equal
&&	Booleans	Logical AND
||	Booleans	Logical OR
.	object.property	Property access
[]	array[integer] array[string]	Array element access
()	function(any, ...)	Function call
new	constructor function	Create a new object using the given constructor
delete	delete object.property	Undefine a property

Operator Precedence

When expressions are evaluated, the operands bind to the operators depending on the precedence of the operators. For example:

a = x + y * z;

This is equivalent to:

a = x + (y * z);

The following table lists the operators in order of highest to lowest precedence.

Operator

. [] () new

++ -- - + delete

* / %

+ -

<< >>

< <= > >=

== !=

&&

||

=

,