Performs a bitwise OR on the value of a variable and the value of an expression and assigns the result to the variable.
Syntax
result |= expression
Parameters
result
Any variable.
expression
Any expression.
Remarks
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 OR operation on them. The result of this operation behaves like this:
0101 (result)
1100 (expression)
----
1101 (output)
Any time either of the expressions has a 1 in a digit, the result has a 1 in that digit. Otherwise, the result has a 0 in that digit.
Requirements
Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards, Internet Explorer 11 standards. Also supported in Store apps (Windows 8 and Windows Phone 8.1). See Version Information.
See Also
Bitwise OR Operator (|)
Operator Precedence
Operator Summary (JavaScript)

