Microsoft JScript
+= Operator
Language Reference
Version 1

See Also


Description
Used to increment a variable by a specified amount.
Syntax
result += expression

The += operator syntax has these parts:

Part Description
result Any variable.
expression Any expression.
Remarks
Using this operator is exactly the same as specifying:

result = result + expression


The underlying subtype of the expressions determines the behavior of the += operator.
If Then
Both expressions are numeric or Boolean Add.
Both expressions are strings Concatenate.
One expression is numeric and the other is a string Concatenate.

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


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