MSDN Library

Bitwise AND Assignment Operator (&=) (JavaScript)

Performs a bitwise AND on the value of a variable and the value of an expression and assigns the result to the variable.

result &= expression


Any variable.


Any expression.

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.

Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards. See Version Information.

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