JavaScript tutorial:
&= Operator

 

The (&=) operator is use to perform a bitwise AND on an expression.

Syntax

result &= expression

The &= operator syntax has these parts:

Part

Description

result

Any variable.

expression

Any expression.

Example

Using this operator is exactly the same as specifying:

result = result & expression

The &= operator looks at the binary representation of the values of result and expression and does a bitwise AND operation on them. The output of this operation behaves like this:

0101 (result)
1100 (expression)
----
0100 (output)

Any time both of the expressions have a 1 in a digit, the result has a 1 in that digit. Otherwise, the result has a 0 in that digit.

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

See also: & Operator, Operator Behavior, Operator Precedence, Operator Summary