JavaScript tutorial:
|| Operator

The (||) operator (logical OR operator) is use to perform a logical disjunction on two expressions.

Syntax

result = expression1 || expression2

The || operator syntax has these parts:

Part	Description
result	Any variable.
expression1	Any expression.
expression2	Any expression.

Example

If either or both expressions evaluate to True, result is True. The following table illustrates how result is determined:

If expression1 is	And expression2 is	The result is
True	True	True
True	False	True
False	True	True
False	False	False

For information on when a run-time error is generated by the || operator, see the Operator Behavior table.

JavaScript uses the following rules for converting non-Boolean values to Boolean values:

• All objects are considered true.

• Strings are considered false if and only if they are empty.

• null and undefined are considered false.

• Numbers are false if, and only if, they are 0

See also: Operator Behavior, Operator Precedence, Operator Summary