JavaScript tutorial:
&& Operator

 

The (&&) operator is use to perform a logical conjunction 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, and only if, both expressions evaluate to True, result is True. If either expression evaluates to False, result is 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 zero.

See also: Operator Behavior, Operator Precedence, Operator Summary

 

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